Biotechnology Research International

Production of Pectinolytic Enzymes by the Yeast Wickerhanomyces anomalus Isolated from Citrus Fruits Peels

María A. Martos, Emilce R. Zubreski, Oscar A. Garro, and Roque A. Hours — Wed, 17 Apr 2013 09:09:21 +0000

Wickerhamomyces anomalus is pectinolytic yeast isolated from citrus fruits peels in the province of Misiones, Argentine. In the present work, enzymes produced by this yeast strain were characterized, and polygalacturonase physicochemical properties were determined in order to evaluate the application of the supernatant in the maceration of potato tissues. W. anomalus was able to produce PG in liquid medium containing glucose and citrus pectin, whose mode of action was mainly of endo type. The supernatant did not exhibit esterase or lyase activity. No others enzymes, capable of hydrolyzing cell wall polymers, such as cellulases and xylanases, were detected. PG showed maximal activity at pH 4.5 and at temperature range between 40°C and 50°C. It was stable in the pH range from 3.0 to 6.0 and up to 50°C at optimum pH. The enzymatic extract macerated potato tissues efficiently. Volume of single cells increased with the agitation speed. The results observed make the enzymatic extract produced by W. anomalus appropriate for future application in food industry, mainly for the production of fruit nectars or mashed of vegetables such as potato or cassava, of regional interest in the province of Misiones, Argentine.

Antioxidant and Hepatoprotective Properties of Tofu (Curdle Soymilk) against Acetaminophen-Induced Liver Damage in Rats

Ndatsu Yakubu, Ganiyu Oboh, and Amuzat Aliyu Olalekan — Thu, 28 Feb 2013 14:06:23 +0000

The antioxidant and hepatoprotective properties of tofu using acetaminophen to induce liver damage in albino rats were evaluated. Tofus were prepared using calcium chloride, alum, and steep water as coagulants. The polyphenols of tofu were extracted and their antioxidant properties were determined. The weight gain and feed intake of the rats were measured. The analysis of serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) activities and the concentrations of albumin, total protein, cholesterol, and bilirubin were analyzed. The result reveals that the antioxidant property of both soluble and bound polyphenolic extracts was significantly higher in all tofus, but the steep water coagulated tofu was recorded higher. Rats fed with various tofus and acetaminophen had their serum ALP, ALT, AST, and LDH activities; total cholesterol; and bilirubin levels significantly () reduced, and total protein and albumin concentrations increased when compared with basal diet and acetaminophen administered group. Therefore, all tofus curdled with various coagulants could be used to prevent liver damage caused by oxidative stress.

Statistical Analysis of Metal Chelating Activity of Centella asiatica and Erythroxylum cuneatum Using Response Surface Methodology

R. J. Mohd Salim, M. I. Adenan, A. Amid, M. H. Jauri, and A. S. Sued — Wed, 27 Feb 2013 07:21:14 +0000

The purpose of the study is to evaluate the relationship between the extraction parameters and the metal chelating activity of Centella asiatica (CA) and Erythroxylum cuneatum (EC). The response surface methodology was used to optimize the extraction parameters of methanolic extract of CA and EC with respect to the metal chelating activity. For CA, Run 17 gave optimum chelating activity with IC50 = 0.93 mg/mL at an extraction temperature of 25°C, speed of agitation at 200 rpm, ratio of plant material to solvent at 1 g : 45 mL and extraction time at 1.5 hour. As for EC, Run 13 with 60°C, 200 rpm, 1 g : 35 mL and 1 hour had metal chelating activity at IC50 = 0.3817 mg/mL. Both optimized extracts were further partitioned using a solvent system to evaluate the fraction responsible for the chelating activity of the plants. The hexane fraction of CA showed potential activity with chelating activity at IC50 = 0.090 and the ethyl acetate fraction of EC had IC50 = 0.120 mg/mL. The study showed that the response surface methodology helped to reduce the extraction time, temperature and agitation and subsequently improve the chelating activity of the plants in comparison to the conventional method.

Production of Enzymes from Agroindustrial Wastes by Biosurfactant-Producing Strains of Bacillus subtilis

Tue, 26 Feb 2013 13:42:51 +0000

Bacteria in the genus Bacillus are the source of several enzymes of current industrial interest. Hydrolases, such as amylases, proteases, and lipases, are the main enzymes consumed worldwide and have applications in a wide range of products and industrial processes. Fermentation processes by Bacillus subtilis using cassava wastewater as a substrate are reported in the technical literature; however, the same combination of microorganisms and this culture medium is limited or nonexistent. In this paper, the amylase, protease, and lipase production of ten Bacillus subtilis strains previously identified as biosurfactant producers in cassava wastewater was evaluated. The LB1a and LB5a strains were selected for analysis using a synthetic medium and cassava wastewater and were identified as good enzyme producers, especially of amylases and proteases. In addition, the enzymatic activity results indicate that cassava wastewater was better than the synthetic medium for the induction of these enzymes.

Family-Specific Degenerate Primer Design: A Tool to Design Consensus Degenerated Oligonucleotides

Thu, 21 Feb 2013 13:54:30 +0000

Designing degenerate PCR primers for templates of unknown nucleotide sequence may be a very difficult task. In this paper, we present a new method to design degenerate primers, implemented in family-specific degenerate primer design (FAS-DPD) computer software, for which the starting point is a multiple alignment of related amino acids or nucleotide sequences. To assess their efficiency, four different genome collections were used, covering a wide range of genomic lengths: Arenavirus ( nucleotides), Baculovirus ( to bp), Lactobacillus sp. ( to bp), and Pseudomonas sp. ( to bp). In each case, FAS-DPD designed primers were tested computationally to measure specificity. Designed primers for Arenavirus and Baculovirus were tested experimentally. The method presented here is useful for designing degenerate primers on collections of related protein sequences, allowing detection of new family members.

Structural Variations of Human Glucokinase Glu256Lys in MODY2 Condition Using Molecular Dynamics Study

Wed, 13 Feb 2013 13:58:12 +0000

Glucokinase (GK) is the predominant hexokinase that acts as glucose sensor and catalyses the formation of Glucose-6-phosphate. The mutations in GK gene influence the affinity for glucose and lead to altered glucose levels in blood causing maturity onset diabetes of the young type 2 (MODY2) condition, which is one of the prominent reasons of type 2 diabetic condition. In view of the importance of mutated GK resulting in hyperglycemic condition, in the present study, molecular dynamics simulations were carried out in intact and 256 E-K mutated GK structures and their energy values and conformational variations were correlated. Energy variations were observed in mutated GK (3500 Kcal/mol) structure with respect to intact GK (5000 Kcal/mol), and it showed increased γ-turns, decreased β-turns, and more helix-helix interactions that affected substrate binding region where its volume increased from 1089.152 Å2 to 1246.353 Å2. Molecular docking study revealed variation in docking scores (intact = −12.199 and mutated = −8.383) and binding mode of glucose in the active site of mutated GK where the involvement of A53, S54, K56, K256, D262 and Q286 has resulted in poor glucose binding which probably explains the loss of catalytic activity and the consequent prevailing of high glucose levels in MODY2 condition.

Display of the Viral Epitopes on Lactococcus lactis: A Model for Food Grade Vaccine against EV71

Wed, 13 Feb 2013 09:07:33 +0000

In this study, we have developed a system for display of antigens of Enterovirus type 71 (EV71) on the cell surface of L. lactis. The viral capsid protein (VP1) gene from a local viral isolate was utilized as the candidate vaccine for the development of oral live vaccines against EV71 using L. lactis as a carrier. We expressed fusion proteins in E. coli and purified fusion proteins were incubated with L. lactis. We confirmed that mice orally fed with L. lactis displaying these fusion proteins on its surface were able to mount an immune response against the epitopes of EV71. This is the first example of an EV71 antigen displayed on the surface of a food grade organism and opens a new perspective for alternative vaccine strategies against the EV71. We believe that the method of protein docking utilized in this study will allow for more flexible presentations of short peptides and proteins on the surface of L. lactis to be useful as a delivery vehicle.

Optimization of Culture Conditions for Some Identified Fungal Species and Stability Profile of -Galactosidase Produced

A. S. Chauhan, N. Srivastava, H. K. Kehri, and B. Sharma — Mon, 28 Jan 2013 10:23:43 +0000

Microbial α-galactosidase preparations have implications in medicine and in the modification of various agricultural products as well. In this paper, four isolated fungal strains such as AL-3, WF-3, WP-4 and CL-4 from rhizospheric soil identified as Penicillium glabrum (AL-3), Trichoderma evansii (WF-3), Lasiodiplodia theobromae (WP-4) and Penicillium flavus (CL-4) based on their morphology and microscopic examinations, are screened for their potential towards α-galactosidases production. The culture conditions have been optimized and supplemented with specific carbon substrates (1%, w/v) by using galactose-containing polysaccharides like guar gum (GG), soya casein (SC) and wheat straw (WS). All strains significantly released galactose from GG, showing maximum production of enzyme at 7th day of incubation in rotary shaker (120 rpm) that is 190.3, 174.5, 93.9 and 28.8 U/mL, respectively, followed by SC and WS. The enzyme activity was stable up to 7days at −20°C, then after it declines. This investigation reveals that AL-3 show optimum enzyme activity in guar gum media, whereas WF-3 exhibited greater enzyme stability. Results indicated that the secretion of proteins, enzyme and the stability of enzyme activity varied not only from one strain to another but also differed in their preferences of utilization of different substrates.

Bioprocessing of “Hair Waste” by Paecilomyces lilacinus as a Source of a Bleach-Stable, Alkaline, and Thermostable Keratinase with Potential Application as a Laundry Detergent Additive: Characterization and Wash Performance Analysis

Ivana A. Cavello, Roque A. Hours, and Sebastián F. Cavalitto — Mon, 17 Dec 2012 13:15:40 +0000

Paecilomyces lilacinus (Thom) Samson LPS 876, a locally isolated fungal strain, was grown on minimal mineral medium containing “hair waste,” a residue from the hair-saving unhairing process, and produced a protease with keratinolytic activity. This enzyme was biochemically characterized. The optimum reaction conditions, determined with a response surface methodology, were 60°C and pH 6.0. It was remarkably stable in a wide range of pHs and temperatures. Addition of Ca2+, Mg2+, or sorbitol was found to be effective in increasing thermal stability of the protease. PMSF and Hg2+ inhibited the proteolytic activity indicating the presence of a thiol-dependent serine protease. It showed high stability toward surfactants, bleaching agents, and solvents. It was also compatible with commercial detergents (7 mg/mL) such as Ariel, Skip, Drive, and Ace, retaining more than 70% of its proteolytic activity in all detergents after 1 h of incubation at 40°C. Wash performance analysis revealed that this protease could effectively remove blood stains. From these properties, this enzyme may be considered as a potential candidate for future use in biotechnological processes, as well as in the formulation of laundry detergents.

Production of a Thermostable and Alkaline Chitinase by Bacillus thuringiensis subsp. kurstaki Strain HBK-51

Secil Berna Kuzu, Hatice Korkmaz Güvenmez, and Aziz Akin Denizci — Thu, 13 Dec 2012 15:23:54 +0000

This paper reports the isolation and identification of chitinase-producing Bacillus from chitin-containing wastes, production of a thermostable and alkaline chitinasese, and enzyme characterization. Bacillus thuringiensis subsp. kurstaki HBK-51 was isolated from soil and was identified. Chitinase was obtained from supernatant of B. thuringiensis HBK-51 strain and showed its optimum activity at 110°C and at pH 9.0. Following 3 hours of incubation period, the enzyme showed a high level of activity at 110°C (96% remaining activity) and between pH 9.0 and 12.0 (98% remaining activity). Considering these characteristics, the enzyme was described as hyperthermophile-thermostable and highly alkaline. Two bands of the enzyme weighing 50 and 125 kDa were obtained following 12% SDS-PAGE analyses. Among the metal ions and chemicals used, Ni2+ (32%), K+ (44%), and Cu2+ (56%) increased the enzyme activity while EDTA (7%), SDS (7%), Hg2+ (11%), and ethyl-acetimidate (20%) decreased the activity of the enzyme. Bacillus thuringiensis subsp. kurstaki HBK-51 is an important strain which can be used in several biotechnological applications as a chitinase producer.

Isolation and Characterization of Some Phytochemicals from Indian Traditional Plants

Neeharika Srivastava, Aishwarya Singh Chauhan, and Bechan Sharma — Tue, 11 Dec 2012 10:29:41 +0000

The present study was designed to evaluate relative contribution of different polyphenols (total phenolics, flavonoids, flavonols) and their antioxidants activities in aqueous extracts of different parts of some plants; Argemone mexicana, Datura metel, Calotropis procera, Thevetia peruviana, and Cannabis sativa. The antioxidants (total phenolics, flavonoids, flavones) were determined by chemical methods. The antioxidant capacities of these extracts were evaluated by FRAP assay. The results demonstrated that phenolic content was maximally present in leaves of T. peruviana. This plant exhibited minimum phenolic content in its flower as compared to other plants. The flower of D. metel contained maximum phenolic content. The flavonoids were present in highest quantity in leaves of C. procera while T. peruviana flowers showed maximum flavonoid content. The fruits of C. sativa contained maximum quantity of flavonoid as compared to other plants tested. The flower extract of C. sativa possessed highest FRAP value followed by A. mexicana and fruit of C. procera. The values of ratios of different polyphenolic compounds present in plant extracts indicated that flower of D. metel contained maximum total flavonoids and minimum phenolics. These results suggested that levels of total phenolics, flavonoids and their FRAP indices exhibited specificity to different plants and their parts.

Properties and Therapeutic Application of Bromelain: A Review

Rajendra Pavan, Sapna Jain, Shraddha, and Ajay Kumar — Mon, 10 Dec 2012 15:17:08 +0000

Bromelain belongs to a group of protein digesting enzymes obtained commercially from the fruit or stem of pineapple. Fruit bromelain and stem bromelainare prepared differently and they contain different enzymatic composition. “Bromelain” refers usually to the “stem bromelain.” Bromelain is a mixture of different thiol endopeptidases and other components like phosphatase, glucosidase, peroxidase, cellulase, escharase, and several protease inhibitors. In vitro and in vivo studies demonstrate that bromelain exhibits various fibrinolytic, antiedematous, antithrombotic, and anti-inflammatory activities. Bromelain is considerably absorbable in the body without losing its proteolytic activity and without producing any major side effects. Bromelain accounts for many therapeutic benefits like the treatment of angina pectoris, bronchitis, sinusitis, surgical trauma, and thrombophlebitis, debridement of wounds, and enhanced absorption of drugs, particularly antibiotics. It also relieves osteoarthritis, diarrhea, and various cardiovascular disorders. Bromelain also possesses some anticancerous activities and promotes apoptotic cell death. This paper reviews the important properties and therapeutic applications of bromelain, along with the possible mode of action.

High-Frequency Regeneration of the Drought-Tolerant Tree Melia volkensii Gurke Using Low-Cost Agrochemical Thidiazuron

Tue, 27 Nov 2012 09:15:24 +0000

Melia volkensii Gurke is a drought-tolerant tree native to East Africa’s arid and semiarid lands (ASALs), with vast but underutilized potential for agroforestry and sustainable livelihoods in the ASALs. Its cultivation is limited by difficulties in propagation via conventional means. Full exploitation of the ability of thidiazuron (TDZ) to elicit regeneration in plant tissue cultures, as sole plant growth regulator (PGR), is hampered by high costs. This study tested the effectiveness of a low-cost agrochemical TDZ for in vitro propagation of M. volkensii. Zygotic embryos from mature seeds were cultured on Gamborg’s B5 medium containing 0 to 4 mg/L of agrochemical TDZ from Kingtai Chemicals Co.,Ltd., China. Callus induction frequency was 96.67 to 100%. Significantly large callus fresh mass was produced at 0.05 mg/L TDZ concentration (ANOVA, ). The effect of TDZ on embryogenicity was significant over certain ranges of concentrations (Anova, ). Multiple somatic embryos developed within 14 days of subculture to hormone-free B5 medium. Somatic embryos developed into microshoots which elongated when transferred to MS medium supplemented with 0.1 mg/L 6-benzylaminopurine plus 10% coconut water. The Kingtai-TDZ showed a high potency and suitability for use in M. volkensii tissue culture.

Production of Alkaline Cellulase by Fungi Isolated from an Undisturbed Rain Forest of Peru

Mon, 19 Nov 2012 11:38:31 +0000

Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL−1) with higher specific productivities (>30 U g−1 h−1). Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry.

In Vitro Propagation of Muña-Muña (Clinopodium odorum (Griseb.) Harley)

Thu, 18 Oct 2012 14:19:04 +0000

A micropropagation protocol was developed which may assist in the safeguarding and augmentation of dwindling natural populations of Clinopodium odorum (Griseb.) Harley, a critically and endangered medicinal plant. Factors affecting culture initiation bud sprouting and growth, rooting, and acclimatization were studied, using nodal segments of in vitro germinated seedling as primary explants on six media supplemented with different concentrations and combinations of 6-benzylaminopurine (BAP) (0.5–1.5 and 2-Naphthalene acetic acid (NAA) (0.5–1.5). Best results for culture initiation with sustainable multiplication rates (100%) were obtained on WP medium without any growth regulator. WP with the addition of 0.5 : 1 or 0.5 : 1.5) of BAP and NAA promoted a higher elongation; however, the optimum number of nodes were obtained in plantlets grown on 1/2 MS with the addition of 1 : 1.5 of BAP and NAA. Culture of sectioned individual nodes transferred to the media with different rates of BAP and NAA 1/2 MS-9 (1.5 : 1.5), SH-8 (1.5 : 1.0), and 1/2 B5-4 (1.0 : 0.5) media resulted in no proliferated shoots. The in vitro plants were successfully acclimatized garden soil and sand (2 : 1) in the greenhouse, with over 90% survival rate. The in vitro-grown plants could be transferred to ex vitro conditions and the efficacy in supporting ex vitro growth was assessed, with a view to develope longer-term strategies for the transfer and reintroduction into natural habitats.

Recent Advances in the Genetic Transformation of Coffee

M. K. Mishra and A. Slater — Wed, 29 Aug 2012 14:27:23 +0000

Coffee is one of the most important plantation crops, grown in about 80 countries across the world. The genus Coffea comprises approximately 100 species of which only two species, that is, Coffea arabica (commonly known as arabica coffee) and Coffea canephora (known as robusta coffee), are commercially cultivated. Genetic improvement of coffee through traditional breeding is slow due to the perennial nature of the plant. Genetic transformation has tremendous potential in developing improved coffee varieties with desired agronomic traits, which are otherwise difficult to achieve through traditional breeding. During the last twenty years, significant progress has been made in coffee biotechnology, particularly in the area of transgenic technology. This paper provides a detailed account of the advances made in the genetic transformation of coffee and their potential applications.

Characterization of Myelomonocytoid Progenitor Cells with Mesenchymal Differentiation Potential Obtained by Outgrowth from Pancreas Explants

Marc-Estienne Roehrich and Giuseppe Vassalli — Tue, 21 Aug 2012 17:06:43 +0000

Progenitor cells can be obtained by outgrowth from tissue explants during primary ex vivo tissue culture. We have isolated and characterized cells outgrown from neonatal mouse pancreatic explants. A relatively uniform population of cells showing a distinctive morphology emerged over time in culture. This population expressed monocyte/macrophage and hematopoietic markers (CD11b+ and CD45+), and some stromal-related markers (CD44+ and CD29+), but not mesenchymal stem cell (MSC)-defining markers (CD90− and CD105−) nor endothelial (CD31−) or stem cell-associated markers (CD133− and stem cell antigen-1; Sca-1−). Cells could be maintained in culture as a plastic-adherent monolayer in culture medium (MesenCult MSC) for more than 1 year. Cells spontaneously formed sphere clusters “pancreatospheres” which, however, were nonclonal. When cultured in appropriate media, cells differentiated into multiple mesenchymal lineages (fat, cartilage, and bone). Positive dithizone staining suggested that a subset of cells differentiated into insulin-producing cells. However, further studies are needed to characterize the endocrine potential of these cells. These findings indicate that a myelomonocytoid population from pancreatic explant outgrowths has mesenchymal differentiation potential. These results are in line with recent data onmonocyte-derivedmesenchymal progenitors (MOMPs).

Novel Simplified and Rapid Method for Screening and Isolation of Polyunsaturated Fatty Acids Producing Marine Bacteria

Ashwini Tilay and Uday Annapure — Wed, 15 Aug 2012 15:43:48 +0000

Bacterial production of polyunsaturated fatty acids (PUFAs) is a potential biotechnological approach for production of valuable nutraceuticals. Reliable method for screening of number of strains within short period of time is great need. Here, we report a novel simplified method for screening and isolation of PUFA-producing bacteria by direct visualization using the H2O2-plate assay. The oxidative stability of PUFAs in growing bacteria towards added H2O2 is a distinguishing characteristic between the PUFAs producers (no zone of inhibition) and non-PUFAs producers (zone of inhibition) by direct visualization. The confirmation of assay results was performed by injecting fatty acid methyl esters (FAMEs) produced by selected marine bacteria to Gas Chromatography-Mass Spectrometry (GCMS). To date, this assay is the most effective, inexpensive, and specific method for bacteria producing PUFAs and shows drastically reduction in the number of samples thus saves the time, effort, and cost of screening and isolating strains of bacterial PUFAs producers.

Optimization of Fermentation Medium for the Production of Glucose Isomerase Using Streptomyces sp. SB-P1

Sheetal Bhasin and H. A. Modi — Thu, 26 Jul 2012 08:36:42 +0000

The combination of medium ingredients has a profound influence on the metabolic pathways running in the microorganism which regulates the production of numerous metabolites. Glucose isomerase (GI), an enzyme with huge potential in the market, can isomerise glucose into fructose. GI is used widely for the production of High-Fructose Corn Syrup (HFCS). HFCS is used as a sweetener in food and pharmaceutical industries. Streptomyces are well-known producers of numerous enzymes including glucose isomerase. An array of 75 isolates was screened for the production of glucose isomerase. The isolate Streptomyces sp. SB-P1 was found to produce maximum amount of extracellular GI. Sucrose and raffinose among pure carbon sources and corn cob and wheat husk among crude agro residues were found to yield high enzyme titers. Potassium nitrate among pure nitrogen sources and soy residues among crude sources gave maximum production. Quantitative effect of carbon, nitrogen, and inducer on GI was also determined. Plackett-Burman design was used to study the effect of different medium ingredients. Sucrose and xylose as carbon sources and peptone and soy residues as nitrogen sources proved to be beneficial for GI production.

Cellulosic Ethanol Production by Recombinant Cellulolytic Bacteria Harbouring pdc and adh II Genes of Zymomonas mobilis

Fri, 20 Jul 2012 14:41:02 +0000

The ethanol fermenting genes such as pyruvate decarboxylase (pdc) and alcohol dehydrogenase II (adh II) were cloned from Zymomonas mobilis and transformed into three different cellulolytic bacteria, namely Enterobacter cloacae JV, Proteus mirabilis JV and Erwinia chrysanthemi and their cellulosic ethanol production capability was studied. Recombinant E. cloacae JV was found to produce 4.5% and 3.5% (v/v) ethanol, respectively, when CMC and 4% NaOH pretreated bagasse were used as substrates, whereas recombinant P. mirabilis and E. chrysanthemi with the same substrates could only produce 4%, 3.5%, 1%, and 1.5 % of ethanol, respectively. The recombinant E. cloacae strain produced twofold higher percentage of ethanol than the wild type. The recombinant E. cloacae strain could be improved further by increasing its ethanol tolerance capability through media optimization and also by combining multigene cellulase expression for enhancing ethanol production from various types of lignocellulosic biomass so that it can be used for industrial level ethanol production.

Experimental Investigations on the Effects of Carbon and Nitrogen Sources on Concomitant Amylase and Polygalacturonase Production by Trichoderma viride BITRS-1001 in Submerged Fermentation

Arotupin Daniel Juwon and Ogunmolu Funso Emmanuel — Sun, 15 Jul 2012 11:55:17 +0000

The paper investigates the effects of different commercial carbon and nitrogen sources on the concomitant synthesis of amylase and polygalacturonase enzymes with the aim of optimizing them for maximal enzyme production. The microorganism used in this work was the fungus Trichoderma viride BITRS-1001, which had been previously identified as a highly active producer of amylase and polygalacturonase enzymes. The results showed that the different commercial carbon and nitrogen substrate significantly affected the concomitant syntheses of amylase and polygalacturonase in culture media supplemented with the different commercial carbon and nitrogen substrates. The result obtained suggested that for optimal and concomitant synthesis of the enzymes by Trichoderma viride BITRS-1001 in submerged fermentation, minimal medium supplemented with maltose and casein were the carbon and nitrogen substrates of choice.

Functional Cloning and Expression of the Schizophyllum commune Glucuronoyl Esterase Gene and Characterization of the Recombinant Enzyme

Thu, 05 Jul 2012 10:40:09 +0000

The gene encoding Schizophyllum commune glucuronoyl esterase was identified in the scaffold 17 of the genome, containing two introns of 50 bp and 48 bp, with a transcript sequence of 1179 bp. The gene was synthesized and cloned into Pichia pastoris expression vector pGAPZα to achieve constitutive expression and secretion of the recombinant enzyme in soluble active form. The purified protein was 53 kD with glycosylation and had an acidic pI of 3.7. Activity analysis on several uronic acids and their derivatives suggests that the enzyme recognized only esters of 4-O-methyl-D-glucuronic acid derivatives, even with a 4-nitrophenyl aglycon but did not hydrolyze the ester of D-galacturonic acid. The kinetic values were 𝐾𝑚 0.25 mM, 𝑉max 16.3 μM·min−1, and 𝑘cat 9.27 s−1 with 4-nitrophenyl 2-O-(methyl 4-O-methyl-α-D-glucopyranosyluronate)-β-D-xylopyranoside as the substrate.

Involvement of the Ligninolytic System of White-Rot and Litter-Decomposing Fungi in the Degradation of Polycyclic Aromatic Hydrocarbons

Natalia N. Pozdnyakova — Thu, 05 Jul 2012 10:31:46 +0000

Polycyclic aromatic hydrocarbons (PAHs) are natural and anthropogenic aromatic hydrocarbons with two or more fused benzene rings. Because of their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, PAHs are a significant environmental concern. Ligninolytic fungi, such as Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus, have the capacity of PAH degradation. The enzymes involved in the degradation of PAHs are ligninolytic and include lignin peroxidase, versatile peroxidase, Mn-peroxidase, and laccase. This paper summarizes the data available on PAH degradation by fungi belonging to different ecophysiological groups (white-rot and litter-decomposing fungi) under submerged cultivation and during mycoremediation of PAH-contaminated soils. The role of the ligninolytic enzymes of these fungi in PAH degradation is discussed.

Physiochemical Characterization of Briquettes Made from Different Feedstocks

C. Karunanithy, Y. Wang, K. Muthukumarappan, and S. Pugalendhi — Wed, 27 Jun 2012 10:01:54 +0000

Densification of biomass can address handling, transportation, and storage problems and also lend itself to an automated loading and unloading of transport vehicles and storage systems. The purpose of this study is to compare the physicochemical properties of briquettes made from different feedstocks. Feedstocks such as corn stover, switchgrass, prairie cord grass, sawdust, pigeon pea grass, and cotton stalk were densified using a briquetting system. Physical characterization includes particle size distribution, geometrical mean diameter (GMD), densities (bulk and true), porosity, and glass transition temperature. The compositional analysis of control and briquettes was also performed. Statistical analyses confirmed the existence of significant differences in these physical properties and chemical composition of control and briquettes. Correlation analysis confirms the contribution of lignin to bulk density and durability. Among the feedstocks tested, cotton stalk had the highest bulk density of 964 kg/m3 which is an elevenfold increase compared to control cotton stalk. Corn stover and pigeon pea grass had the highest (96.6%) and lowest (61%) durability.

Ethanol Production from Nondetoxified Dilute-Acid Lignocellulosic Hydrolysate by Cocultures of Saccharomyces cerevisiae Y5 and Pichia stipitis CBS6054

Ping Wan, Dongmei Zhai, Zhen Wang, Xiushan Yang, and Shen Tian — Tue, 26 Jun 2012 09:07:15 +0000

Saccharomyces cerevisiae Y5 (CGMCC no. 2660) and Issatchenkia orientalis Y4 (CGMCC no. 2159) were combined individually with Pichia stipitis CBS6054 to establish the cocultures of Y5 + CBS6054 and Y4 + CBS6054. The coculture Y5 + CBS6054 effectively metabolized furfural and HMF and converted xylose and glucose mixture to ethanol with ethanol concentration of 16.6 g/L and ethanol yield of 0.46 g ethanol/g sugar, corresponding to 91.2% of the maximal theoretical value in synthetic medium. Accordingly, the nondetoxified dilute-acid hydrolysate was used to produce ethanol by co-culture Y5 + CBS6054. The co-culture consumed glucose along with furfural and HMF completely in 12 h, and all xylose within 96 h, resulting in a final ethanol concentration of 27.4 g/L and ethanol yield of 0.43 g ethanol/g sugar, corresponding to 85.1% of the maximal theoretical value. The results indicated that the co-culture of Y5 + CBS6054 was a satisfying combination for ethanol production from non-detoxified dilute-acid lignocellulosic hydrolysates. This co-culture showed a promising prospect for industrial application.

Biodegradation of Used Motor Oil in Soil Using Organic Waste Amendments

O. P. Abioye, P. Agamuthu, and A. R. Abdul Aziz — Wed, 20 Jun 2012 19:11:22 +0000

Soil and surface water contamination by used lubricating oil is a common occurrence in most developing countries. This has been shown to have harmful effects on the environment and human beings at large. Bioremediation can be an alternative green technology for remediation of such hydrocarbon-contaminated soil. Bioremediation of soil contaminated with 5% and 15% (w/w) used lubricating oil and amended with 10% brewery spent grain (BSG), banana skin (BS), and spent mushroom compost (SMC) was studied for a period of 84 days, under laboratory condition. At the end of 84 days, the highest percentage of oil biodegradation (92%) was recorded in soil contaminated with 5% used lubricating oil and amended with BSG, while only 55% of oil biodegradation was recorded in soil contaminated with 15% used lubricating oil and amended with BSG. Results of first-order kinetic model to determine the rate of biodegradation of used lubricating oil revealed that soil amended with BSG recorded the highest rate of oil biodegradation (0.4361 day−1) in 5% oil pollution, while BS amended soil recorded the highest rate of oil biodegradation (0.0556 day−1) in 15% oil pollution. The results of this study demonstrated the potential of BSG as a good substrate for enhanced remediation of hydrocarbon contaminated soil at low pollution concentration.

Polymorphism of Myostatin Gene in Intron 1 and 2 and Exon 3, and Their Associations with Yearling Weight, Using PCR-RFLP and PCR-SSCP Techniques in Zel Sheep

Wed, 20 Jun 2012 19:10:52 +0000

The aim of present study was to investigate myostatin gene polymorphism and its association with yearling weight records in Zel sheep using PCR-RFLP and PCR-SSCP methods. Blood samples were collected from 200 Zel sheep, randomly, and DNA was extracted using modified salting out method. Polymerase chain reaction was carried out to amplify 337, 222, and 311 bp fragments, respectively, comprising a part of exon 3, intron 1, and intron 2 of myostatin gene. In addition, exon 3 was digested by HaeIII enzyme under RFLP method, and introns 1 and 2 were studied using SSCP. Under RFLP method, all samples showed mm genotype. Under SSCP method, intron 1 was also monomorph but intron 2 was polymorph (AA, AB, and BB). The allelic frequencies for A and B were 75.5 and 24.5%, respectively. This locus was not in Hardy-Weinberg equilibrium (𝑃<0.05), and there was no significant effect of myostatin gene on yearling weights.

Optimization of the Nutritional Parameters for Enhanced Production of B. subtilis SPB1 Biosurfactant in Submerged Culture Using Response Surface Methodology

Ines Mnif, Semia Chaabouni-Ellouze, and Dhouha Ghribi — Mon, 07 May 2012 14:59:42 +0000

Nutritional requirements can contribute considerably to the production cost and the bioprocess economics. Media optimisation using response surface methodology is one of the used methods to ameliorate the bioprocess economics. In the present study, biosurfactant production by Bacillus subtilis SPB1 was effectively enhanced by response surface methodology. A Plackett-Burman-based statistical screening procedure was adopted to determine the most important factor affecting lipopeptide production. Eleven variables are screened and results show that glucose, K2HPO4, and urea concentrations influence the most biosurfactant production. A Central Composite Design was conducted to optimize the three selected factors. Statistical analyses of the data of model fitting were done by using NemrodW. Results show a maximum predicted biosurfactant concentration of 2.93 (±0.32) g/L when using 15 g/L glucose, 6 g/L urea, and 1 g/L K2HPO4. The predicted value is approximately 1.65 much higher than the original production determined by the conventional one-factor-at-a-time optimization method.

Biotechnological Tools for Environmental Sustainability: Prospects and Challenges for Environments in Nigeria—A Standard Review

Thu, 03 May 2012 14:03:59 +0000

The environment is a very important component necessary for the existence of both man and other biotic organisms. The degree of sustainability of the physical environment is an index of the survival and well-being of the entire components in it. Additionally, it is not sufficient to try disposing toxic/deleterious substances with any known method. The best method of sustaining the environment is such that returns back all the components (wastes) in a recyclable way so that the waste becomes useful and helps the biotic and abiotic relationship to maintain an aesthetic and healthy equilibrium that characterizes an ideal environment. In this study, the method investigated includes biological method of environmental sustainability which seeks to investigate the various biotechnological tools (biotools) in current use and those undergoing investigations for future use.

The Diversity of Endophytic Methylotrophic Bacteria in an Oil-Contaminated and an Oil-Free Mangrove Ecosystem and Their Tolerance to Heavy Metals

Wed, 07 Mar 2012 16:25:27 +0000

Methylobacterium strains were isolated from mangrove samples collected in Bertioga, SP, Brazil, from locations either contaminated or uncontaminated by oil spills. The tolerances of the strains to different heavy metals were assessed by exposing them to different concentrations of cadmium, lead, and arsenic (0.1 mM, 0.5 mM, 1 mM, 2 mM, 4 mM, and 8 mM). Additionally, the genetic diversity of Methylobacterium spp. was determined by sequence analysis of the 16S rRNA genes. The isolates from the contaminated locations were grouped, suggesting that oil can select for microorganisms that tolerate oil components and can change the methylotrophic bacterial community. Cadmium is the most toxic heavy metal assessed in this work, followed by arsenic and lead, and two isolates of Methylobacterium were found to be tolerant to all three metals. These isolates have the potential to bioremediate mangrove environments contaminated by oil spills by immobilizing the heavy metals present in the oil.