Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

Table 3

Examples of microbial strains that are used for biofuel production.

Strain name	Strain description	Biofuel type	Titer (g/L)	Yield; (g/g consumed sugar)	Reference
S. cerevisiae 424A (LNH-ST)	Xylose and glucose fermenting strain. Incorporated XR and XDH genes from S. stipitis and over-expressed endogenous xylulokinase gene	Ethanol	45	0.4	[222]
S. cerevisiae TMB3400	Same as above	Ethanol	33	0.51	[223]
S. cerevisiae GLBRC Y35	Same as above	Ethanol	46	0.49	[224]
S. cerevisiae RWB 218	Xylose and glucose fermenting strain. Incorporated XI gene from piromyces; overexpression of endogenous xylulokinase, ribose 5-phosphate isomerase, ribulose 5-phosphate epimerase, transketolase and transaldolase genes; knockout of GRE3 gene, which encodes an aldose reductase.	Ethanol	47	0.38	[225]
S. cerevisiae  DA24-16BT3	Xylose, glucose and cellobiose-fermenting strain. Incorporation of XR and XDH genes for xylose fermentation, and cellodextrin transporter and intracellular β-glucosidase genes for cellobiose consumption	Ethanol	60	0.38	[205]
E. coli KO11	Homoethanolic fermentation strain. Incorporated pyruvate decarboxylase and alcohol dehydrogenase genes (PET operon) from Zymomonas mobilis.	Ethanol	40+	0.44~0.51	[208]
Zymomonas mobilis AX101	Genetically engineered xylose, arabinose and glucose fermenting strain	Ethanol	42+	0.42 (estimated)	[196]
S. stipitis FPL-061	A mutant selected for growth on L-xylose in the presence of respiratory inhibitors	Ethanol	29	0.42	[286]
Clostridium thermocellum LQRI	Native CBP strain	Ethanol	1.4	0.26	[212]
Clostridium phytofermentans ATCC 700394	Native CBP strain	Ethanol	2.8	0.39	[216]
Clostridium  acetobutylicum P262	Native acetone, butanol and ethanol producing strain	Acetone, butanol, and ethanol	2.9/8.1/0.3	0.39	[195]
Clostridium beijerinckii NRRL B593	Native isopropanol, butanol and ethanol producing strain	Isopropanol, butanol, and ethanol	3.2/6.9/0.45	0.32	[241]
E.  coli strains	Abiotic long chain keto acids and alcohols producing strains, achieved through extending branched-chain amino acid pathways	1-Propanol,; isobutanol,; 1-butanol,; 1-pentanol, and so forth	0.007~1.2	N/A	[197]
Saccharomyces cerevisiae	Overexpression of genes in valine metabolism	Isobutanol	<0.1	0.00097	[227]
Saccharomyces cerevisiae	Gevo strains for n-butanol and Isobutanol production; incorporated butanol synthetic pathway from Clostridia species; Built isobutanol pathway either in mitochondria or in the cytosol using endogenous or heterologous genes	n-butanol/isobutanol	N/A	N/A	[226, 228]
Saccharomyces cerevisiae	Butamax/Dupont strains for n-butanol, sec-butanol, and isobutanol production. Incorporated many different heterologous genes and endogenous genes to build butanol synthesis pathways in either mitochondria or cytosol.	n-butanol/sec-butanol/isobutanol	N/A	N/A	[229, 232]
Saccharomyces cerevisiae	Amyris strain for isoprenoid production. Strong expression of Mevalonic acid (MVA) pathway genes and manipulation of many other genes	isoprenoid	N/A	N/A	[232]
Rhodosporidium Toruloides Y4	Lignocellulosic hydrolysate domesticated strain that could consume both glucose and xylose	Lipids	5.5	0.10	[198]
Cryptococcus curvatus	Native oleaginous yeast that could consume both glucose and xylose	Lipids	5.8	0.20	[199]
Lipomyces starkeyi	Native oleaginous yeast that could consume both glucose and xylose	Lipids	4.6	0.16	[199]