Production of novel alkali-thermo-tolerant cellulase-poor xylanases from Coprinopsis cinerea HK-1 NFCCI-2032

Abstract

Culture conditions of a newly isolated basidiomycetous strain were optimized for the enhanced production of extracellular alkali-thermo-tolerant cellulase-poor xylanase using wheat bran as the sole carbon source under solid state fermentation (SSF). SEM and ITS sequencing confirmed it as Coprinopsis cinerea HK-1 NFCCI-2032. Among various inexpensive agro-residues, wheat bran (carbon source) came up as the most potent enzyme inducer under SSF, and resulted in 54% higher xylanase activity compared to that in submerged fermentation mode. The strain grew well even at 47 °C. The highest xylanase (695.8 IU/mL) titer was recorded at a substrate:moisture ratio of 1:3 after 7 days of incubation at 37 °C at pH 6.4 along with 0.541 IU/mL of poorly associated cellulase activity. The xylanase exhibited remarkable stability and retained 50% of its activity at pH 8.0 on incubation at 55 °C for 15 min and 78, 43, and 23% of its activity at temperatures 65, 75 and 85 °C, respectively, demonstrating an approximately 50% alkali-thermo-tolerant nature, which is suitable for biobleaching.