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 4

Viscosity^a of polyglutamic acid^b from Bacillus K.

Rpm of spindle	Viscosity of polymer (1.4%)
	Medium^b + 20 g sodium glutamate/L		Medium^b + 20 g glutamine/L
	+NH4NO3	−NH4NO3	+NH4NO3
5	36	36	60
10	24	30	48
50	2.4	3.4	39.6
100	0	0	34.8

Viscosity (centipoise = 0.01 poise gm⁻¹ cm⁻¹ s) of the broth was measured at 30°C using Brookfield DV II + viscometer using a small sample adapter at a varying spindle speeds. Xanthan gum (0.25%) was used as standard for viscosity (20–60 cp) at various rpm (5–100). ^bPolymer was extracted from broth or solid medium (medium: sodium citrate 20 g/L and glycerol 40 g/L, in Bushnell and Hass medium. Glutamic acid supplemented only where mentioned).
Extraction was done using 3 volumes of acetone and dried at 60°C. Redissolved polymer (fixed concentration) was used for viscosity measurement.