Production of bioethanol as useful biofuel through the bioconversion of water hyacinth (Eichhornia crassipes)

Water hyacinth (Eichhornia crassipes) represents a promising candidate for fuel ethanol production in tropical countries because of their high availability and high biomass yield. Bioconversion of such biomass to bioethanol could be wisely managed through proper technological approach. In this work, pretreatment of water hyacinth (10 %, w/v) with dilute sulfuric acid (2 %, v/v) at high temperature and pressure was integrated in the simulation and economic assessment of the process for further enzymatic saccharification was studied. The maximum sugar yield (425.6 mg/g) through enzymatic saccharification was greatly influenced by the solid content (5 %), cellulase load (30 FPU), incubation time (24 h), temperature (50 °C), and pH (5.5) of the saccharifying medium. Central composite design optimized an ethanol production of 13.6 mg/ml though a mixed fermentation by Saccharomyces cerevisiae (MTCC 173) and Zymomonas mobilis (MTCC 2428). Thus the experiment imparts an economic value to water hyacinths that are cleared from choking waterways.