Evaluation of pretreatment with Pleurotus ostreatus for enzymatic hydrolysis of rice straw.

The effects of biological pretreatment of rice straw using four white-rot fungi (Phanerochaete chrysosporium, Trametes versicolor, Ceriporiopsis subvermispora, and Pleurotus ostreatus) were evaluated on the basis of quantitative and structural changes in the components of the pretreated rice straw as well as susceptibility to enzymatic hydrolysis. Of these white-rot fungi, P. ostreatus selectively degraded the lignin fraction of rice straw rather than the holocellulose component. When rice straw (water content of 60%) was pretreated with P. ostreatus for 60 d, the total weight loss and the degree of Klason lignin degraded were 25% and 41%, respectively. After the pretreatment, the residual amounts of cellulose and hemicellulose were 83% and 52% of those in untreated rice straw, respectively. By enzymatic hydrolysis with a commercial cellulase preparation for 48 h, 52% holocellulose and 44% cellulose in the pretreated rice straw were solubilized. The net sugar yields based on the amounts of holocellulose and cellulose of untreated rice straw were 33% for total soluble sugar from holocellulose and 32% for glucose from cellulose. The SEM observations showed that the increase in susceptibility of rice straw to enzymatic hydrolysis by pretreatment with P. ostreatus is caused by partial degradation of the lignin seal. When the content of Klason lignin was less than 15% of the total weight of the pretreated straw, enhanced degrees of enzymatic solubilization of holocellulose and cellulose fractions were observed as the content of Klason lignin decreased.

[1]  M. Kuwahara,et al.  Screening of basidiomycetes for lignin peroxidase genes using a DNA probe , 2004, Applied Microbiology and Biotechnology.

[2]  Michihiro Fujii,et al.  Continuous simultaneous saccharification and fermentation of delignified rice straw by a combination of two reversibly soluble-autoprecipitating enzymes and pentose-fermenting yeast cells , 1997 .

[3]  Masaaki Kuwahara,et al.  Bioorganosolve pretreatments for simultaneous saccharification and fermentation of beech wood by ethanolysis and white rot fungi. , 2003, Journal of biotechnology.

[4]  G. T. Tsao,et al.  Ethanol production from renewable resources. , 1999, Advances in biochemical engineering/biotechnology.

[5]  J. Dorado,et al.  Nitrogen-removal with protease as a method to improve the selective delignification of hemp stemwood by the white-rot fungus Bjerkandera sp. strain BOS55 , 2001, Applied Microbiology and Biotechnology.

[6]  J. Abeln,et al.  Supercritical Water Oxidation: State of the Art , 1999 .

[7]  N. Meinander,et al.  Main and interaction effects of acetic acid, furfural, and p-hydroxybenzoic acid on growth and ethanol productivity of yeasts. , 1999, Biotechnology and bioengineering.

[8]  A. Hatakka,et al.  Pretreatment of wheat straw by white-rot fungi for enzymic saccharification of cellulose , 1983, European journal of applied microbiology and biotechnology.

[9]  Takuya Yoshida,et al.  Gasification of biomass model compounds and real biomass in supercritical water , 2004 .

[10]  Warren Mabee,et al.  Biorefining of softwoods using ethanol organosolv pulping: preliminary evaluation of process streams for manufacture of fuel-grade ethanol and co-products. , 2005, Biotechnology and bioengineering.

[11]  Takashi Watanabe,et al.  Conversion of Japanese red cedar (Cryptomeria japonica) into a feed for ruminants by white-rot basidiomycetes , 2005 .

[12]  S. Colowick,et al.  Methods in Enzymology , Vol , 1966 .

[13]  Bin Yang,et al.  Fast and efficient alkaline peroxide treatment to enhance the enzymatic digestibility of steam-exploded softwood substrates. , 2002, Biotechnology and bioengineering.

[14]  M. Tien,et al.  Lignin peroxidase of Phanerochaete chrysosporium , 1988 .

[15]  W. Trösch,et al.  Screening of white-rot fungi for biological pretreatment of wheat straw for biogas production , 1986, Applied Microbiology and Biotechnology.

[16]  F. Smith,et al.  COLORIMETRIC METHOD FOR DETER-MINATION OF SUGAR AND RELATED SUBSTANCE , 1956 .

[17]  R. Matsuno,et al.  Effect of Puff Cooking on Structure and Chemical Properties of Several Lignocellulosic Agrowastes , 1985 .

[18]  A. Ferraz,et al.  Molecular weight distribution of wood components extracted from pinus taeda biotreated by Ceriporiopsis subvermispora , 2003 .

[19]  L. Olsson,et al.  Potential inhibitors from wet oxidation of wheat straw and their effect on ethanol production of Saccharomyces cerevisiae: wet oxidation and fermentation by yeast. , 2003, Biotechnology and bioengineering.

[20]  C. Wyman,et al.  Effect of xylan and lignin removal by batch and flowthrough pretreatment on the enzymatic digestibility of corn stover cellulose , 2004, Biotechnology and bioengineering.

[21]  R. Matsuno,et al.  Production of single-cell protein from enzymatic hydrolyzate of rice straw , 1982, European journal of applied microbiology and biotechnology.

[22]  A. Ferraz,et al.  Organosolv delignification of white- and brown-rotted Eucalyptus grandis hardwood. , 2000 .

[23]  Tatsuro Sawada,et al.  Enhanced ethanol production from enzymatically treated steam‐exploded rice straw using extractive fermentation , 2001 .

[24]  R. Matsuno,et al.  Evaluation of chemical pretreatment for enzymatic solubilization of rice straw , 1982, European journal of applied microbiology and biotechnology.

[25]  F. Zadrazil,et al.  Screening of fungi for lignin decomposition and conversion of straw into feed , 1985 .

[26]  M. Galbe,et al.  Process Considerations and Economic Evaluation of Two‐Step Steam Pretreatment for Production of Fuel Ethanol from Softwood , 2004, Biotechnology progress.