2.5. Biomass hydrolysis using Streptomyces cellulase
Since the cellulase preparation from the new isolate was
enriched in endoglucanase (CMCase) activity, the enzyme was
used as a supplement in a commercial cellulase preparation (Zytex
India Ltd., Mumbai) for hydrolysis of dilute acid pretreated sorghum
stover. Preparation of pretreated feedstock and enzymatic
hydrolysis of pretreated sorghum biomass was performed as mentioned
by Akanksha et al. (2014). Hydrolysis was conducted with
10% (w/v) biomass loading, 20 FPUs/g cellulase (zytex) loading
and with 0.15% w/v Tween 80. Cellulase preparation from Streptomyces
was supplemented to the reaction mixture to attain 10 or
5 U of CMCase activity per unit of FPase and hydrolysis were conducted
in 150 ml screw capped flasks in a total volume of 30 ml for
48 h at 50 C with 200 rpm agitation. After the reaction, samples
were centrifuged (10000 rpm for 10 min) to remove unhydrolyzed
residue and total reducing sugars in the supernatant was estimated
by DNS method (Miller, 1959).