PRETREATMENT OF COFFEE PULP BY PHANEROCHAETE CHRYSOSPORIUM

Abstract

. Coffee pulp is one of the abundant sources of agricultural byproducts in Vietnam. Coffee pulp contains high amount of cellulose, which is an important ingredient to be converted into bioethanol. However, in order to sufficiently convert the coffee pulp into ethanol, this material firstly needs to be pretreated to reduce the amount of lignin and hemicellulose while retaining cellulose composition. In this study, the white rot fungus Phanerochaete chrysosporium was used for the pretreatment prior to hydrolysis and fermentation steps. In the conditions of raw material humidity of 85%, environmental temperature of 35^oC and biomass/material ratio of 1.5%. After 40 days of pretreatment, the contents of cellulose, hemicellulose and lignin were reduced by 20.7%, 12.8% and 50.2%, respectively. The pretreated raw materials were then subjected to hydrolysis step using the commercial enzyme complexes (25 FPU/g Viscozyme Cassava and 34 CBU/g Novozyme 188). As a result,  the reducing sugar content of 13.19 g/L and the glucose content of  5.42 g/L with the hydrolyzed efficiency of 60.23%. The results showed that the P. chrysosporium was highly compatible when cultured on the source of coffee pulp biomass and they were able to secrete some enzymes capable of biodegrading cellulose, lignin and hemicellulose into the environment.