Selection of Agricultural Wastes for Biological Pretreatment

Abstract

Different lignocellulosic biomass available in abundance such as cotton hull, sweet sorghum bagasse, rice husk, sugarcane bagasse and corn stover were selected as substrate for biological pretreatment to liberate reducing sugars. They were primarily characterized by analyzing their lignin, cellulose, hemicellulose and reducing sugar content. Cellulose, hemicellulose and lignin content of all the substrates were found in the standard range of 35–50%, 25–30% and 10–25% respectively. Corn stover showed maximum cellulose of 40.26%, Sugarcane bagasse showed maximum hemicellulose and reducing sugars 28.7% and 1.26% respectively. Lignin, the barrier in plant tissue for lignin hydrolysis was found maximum of 27% in rice husk and minimum 19% in corn stover. Biological hydrolysis of all these substrates was carried out using a known lignocellulolytic white rot fungi Phanerochaete chrysosporium. Growth was observed in all the substrates, protein content in growth was found in the range of 0.021–0.300 g % in the cells harvested after 5 d of incubation in solid state fermentation. Cotton hull supported maximum growth of Phanerochaete chrysosporium least being rice husk. During the period of 5 d, 23.8 g % of cellulose was hydrolyzed in cotton hull, followed by 14.6 and 14.1 g % hydrolysis in sweet sorghum bagasse and corn stover respectively. Sugarcane bagasse showed very low hydrolysis of 9.67 g % and no hydrolysis was observed in rice husk. Yeast extract and peptone addition had no effect on cellulose hydrolysis.