Process design for bioconversion of cassava stalk through solid substrate fermentation

Abstract

Cassava stalks are by products from cassava tuber production. Cassava stalks is lignocellulosic material (LM) which is composed by lignin, hemicelullose, and cellulose. Utilization of LM optimally will push a beneficial effort in producing sugar. The presence of lignin can limit the effort to convert cassava stalks into sugar. The lignin have to be reduced. Its introduced solid substrate fermentation (SSF) technique by using molds to optimize utilization of cassava stalks. Molds can produce enzyme for converting LM into sugar. There is no enough information of design process of solid state fermentation for cassava stalks bioconversion, starting from selection of suitable microorganism used, substrate suitability testing, lignin reducing pretreatment, design of fermentor, and the needed of aeration for optimizing molds growth. Based on research result, a process for bioconversion of cassava stalks into sugar through SSF techniques was defined as follow: Microorganism suitable used is Aspergillus niger, cassava stalks suitable as a growth media for mold as a physical support (DMC = 93, 76 %) and source of nutrient (C/N 19, 92), physical pretreatment by reduce the particle size was more suitable than alkaline pretreatment for lignin reduction, and the best fermentor is unforced aeration closed chamber at big capacity.