Industrialization progress of lignocellulosic ethanol

Abstract

Lignocellulose is an abundant and renewable biomass that is mainly composed of cellulose, hemicellulose and lignin. The development and utilization of lignocellulosic ethanol is an effective way to solve the energy problem/crises, In addition, lignocellulosic ethanol industry can play a significant role in controlling environmental pollution and extending agricultural industrial chain; however, it has not been able to realize large-scale industrialization due to the limitation of both biotechnology and economy. This review first introduces industrialization status of lignocellulosic ethanol, and then focuses on the progress of practical technology and analyzing the economic feasibility of the second-generation bioethanol plant; finally, the future development trend of the industry was prospected. To summarize, continuous technological innovation is needed in vital steps such as pretreatment, enzymatic hydrolysis, and fermentation. Meanwhile, for making the cellulosic ethanol industry truly economically competitive, we also need to achieve interdisciplinary, cross-domain integration innovation, such as the construction of raw material collection and storage system, in situ producing special enzyme system, high-value utilization of raw material components, developing a closely integration of biomass refinery with mature equipment and overall industrialization programs, etc. It is hoped that this review can provide a useful reference for the industrialization of second-generation bioethanol.

Fabrication and Characterization of Carbon Nanotube Filled PDMS Hybrid Membranes for Enhanced Ethanol Recovery

“…Specifically, when the concentration of ethanol (product) in the fermentation broth is higher than 10 wt %, the reactivity of fermentation microorganisms and enzymes will be significantly reduced. 6 Therefore, it is necessary to remove the excessive ethanol constantly from the fermenter by coupling reaction and separation, which could then reduce the inhibition effect of ethanol and enhance the reactivity of enzymes and fermentation microorganisms. 7 Currently, the conventional separation methods to extract ethanol from fermentation broth at low concentrations (<10 wt %) include solvent extraction, 8 adsorption, 9 vapor extraction, 10 membrane distillation, 11,12 and pervaporation.…”

“…The main reason for the low efficiency for hydrolysis during fermentation is the product inhibition effect. Specifically, when the concentration of ethanol (product) in the fermentation broth is higher than 10 wt %, the reactivity of fermentation microorganisms and enzymes will be significantly reduced . Therefore, it is necessary to remove the excessive ethanol constantly from the fermenter by coupling reaction and separation, which could then reduce the inhibition effect of ethanol and enhance the reactivity of enzymes and fermentation microorganisms …”