Bioethanol production from bamboo (Dendrocalamus sp.) process waste

Abstract

Bamboo as a feed stock for bioethanol production is interesting due to the relatively higher growth rate of these plants and their abundant and sustainable availability in the tropics. Dendrocalamus are bamboo varieties common in India, of which large amounts of biomass is generated annually as byproducts of bamboo processing industries. In the current study, process waste from bamboo industry was evaluated as a feedstock for bioethanol production by enzymatic saccharification. Dilute alkali pretreatment of the biomass resulted in efficient removal of lignin, effectively increasing the concentration of cellulose to 63.1% from 46.7%. Enzymatic saccharification of pretreated biomass was optimized following a response surface methodology and the optimal set of parameters for maximal saccharification was derived. Pretreatment method could recover 64.31% of the total sugar polymers and a hydrolysis efficiency of 82.36% was achieved. Direct fermentation of the enzymatic hydrolysate was efficient with ethanol production being 71.34% of theoretical maximum (3.08% v/v ethanol yield). Material balances were calculated for the entire process from raw biomass to ethanol and the overall process efficiency was found to be ∼43%. The process has the potential to generate 143 L of ethanol per dry ton of bamboo process waste.