International Journal of Current Microbiology and Applied Sciences

ISSN: 2319-7706 Volume 2 Number 9 (2013) pp. 174-187

Utilization of fortified rice husk for the fermentative production of xylanase by Trichoderma sp.

K.Balakrishnan1 *, Rahul Kumar1 , R Agalya Devi1 , S. Jayasri2 and B.Nishabalu2

1Technology Business Incubator, BIT Sathyamangalam, Erode District 638401, Tamil Nadu, India 2Department of Biotechnology, BIT Sathyamangalam, Erode District 638401, Tamil Nadu, India *Corresponding author e-mail:rainbalu@gmail.com

ABSTRACT

Mineral salt agar plates containing rice husk powder were used for the isolation of xylanase producing microorganisms. Two of the fungal isolates namely Trichoderma sp. and Neurospora sp. showed better xylanase activities. Trichoderma sp. produced maximum xylanase activity (22.5 U/ gds 72 h) when grown in solid substrate than that in submerged cultivation (2.62 U/mL in 96 h). It was further revealed that carboxy methyl cellulose (CMC) as additional carbon source produced maximum rise in xylanase activity (107 U/gds, 72 h) in solid culturing. Similarly the nitrogen sources (casein acid hydrolysate, yeast extract & corn steep solid) supplemented also gave enhanced enzyme activities. Synergistic effect of CMC & corn steep solid resulted in enhanced xylanase activity as high as 570 U/gds in 72 h. The same further enhanced to 722 U/gds when this combination was altered by replacing pressmud extract (PE) with a combination of PE: Corn steep liquor (2:8). The crude xylanase activity was more pronounced at 50°C and at pH 5. Enzyme was stable at 40 to 70°C. Ca2+ Cu 2+ and Fe2+ acted as strong inhibitors for xylanase activity. Three phase partition resulted in 7 fold rise in enzyme activity i.e. 5985 U/mg

Keywords

Rice husk; Trichoderma sp.; SSF; Pressmud Neurospora sp.; Xylanase.