Use of Nonspecific, Glutamic Acid-Free, Media and High Glycerol or High Amylase as Inducing Parameters for Screening Bacillus Isolates Having High Yield of Polyglutamic Acid

Table 1

Primary screening of Bacillus strains producing extracellular polymeric substance (EPS).

Culture	Source^a	Phenotype of colonies on rich media and synthetic medium^b	Identification^c; (16S rDNA and biochemical tests)
Bacillus K.	Soil near oil well	Highly mucoid	Bacillus  licheniformis
Bacillus R.	Seawater	Highly mucoid	Bacillus  licheniformis
Bacillus T.	Soil near petrol pump	Highly mucoid	Bacillus  licheniformis
Bacillus D.	Desert soil	Highly mucoid	Bacillus  licheniformis
Bacillus O.	Fermented soybean flour	Mucoid	Bacillus  licheniformis
Bacillus F.	Fermented gram flour	Mucoid	Bacillus  licheniformis
Bacillus B.	Fungus infested field soil	Variable (mucoid)	Bacillus  subtilis

Isolation of Bacillus: samples were suspended in saline and vortexed; supernatants were heated to 80°C for 15 minutes to kill all vegetative, non-endospore bearing cells. Supernatants were used for direct isolation on solid media.
^bSolid media (without glutamic acid supplementation) for isolation: Luria agar (pH 7–11, NaCl 0–100 g/l) and synthetic medium containing 20 g citrate/l and 40 g glycerol/l (pH 7).
^cBacterial isolates were inoculated into Luria broth and incubated for 18 to 48 h. Gram staining, capsule staining (Maneval’s method), and endospore (Schaeffer and Fulton method) staining done at various intervals. All isolates showed presence of Gram positive rods in chains or single cells with capsule and endospores at different times and were further identified.