第27卷 增刊1 农 业 工 程 学 报 Vol.27 Supp.1

218 2011年 5月 Transactions of the CSAE May. 2011

Recent advances in lignocellulosic ethanol

Zhan Hanhui1, Huang Lilin2

※

（1. School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China;

2. Hunan University of Technology, Zhuzhou 412008, China）

Abstract：Ethanol production from lignocellulosic material has a great potential for wide application. This review article summarized the lignocellulosic ethanol processes such as pretreatment, hydrolysis and fermentative. Moreover, the efficiency of pretreatment methods and xylose fermentation were discussed. Besides, the recent progress of lignocellulosic ethanol, such as fermentative strains, genetic engineering, fermentative processes (e.g. SHF and CBP) and the integration of fermentation and separation were described. Finally, some suggestions for future works with the development of lignocellulosic ethanol were proposed.

Key words: bio-energy, fermentation, genetic engineering, pretreatment, lignocellulosic ethanol doi：10.3969/j.issn.1002-6819.2011.z1.043 CLC number: TK6, TQ920 Document code: A Article ID: 1002-6819(2011)-Supp.1-0218-05 Zhan Hanhui, Huang Lilin. Recent advances in lignocellulosic ethanol [J]. Transactions of the CSAE, 2011, 27(Supp.1): 218－222. (in Chinese with English abstract)

湛含辉，黄丽霖. 木质纤维素乙醇研究进展[J]. 农业工程学报，2011，27(增刊1)：218－222.

0 Introduction

As the fossil fuels is decreasing and the combustion of fossil fuels has serious negative effects on environment because of excess CO2 and sulfur oxide emission, many researchers have been devoting to the exploration of alternative energy resources in the future, such as solar, wind and biomass and so on, which can substitute fossil fuels and are considered as clean, renewable fuels with less pollution[1-2].

Biomass is the fourth largest source of energy in the world after coal, petroleum and natural gas. Presently, biomass energy contains biohydrogen, biogas, biodiesel and bioethanol, which is used for generating electricity, fuel of vehicles and heating. Among the various biomass, bioethanol is an attractive future fuel energy carrier due to its higher octane number, broader flammability limits, higher flame speeds, higher heats of vaporization and less SO2 and CO2 emission. Moreover, the technologies of bioethanol production are more commercially mature, at least for the transportation market[3]. In the past few years, the global ethanol production has been increasing continuously, and China becomes the third largest bio-ethanol producer in the world after the United State and Brazil. Fig. 1 shows the ethanol production and dosages from 2006 to 2009 in USA, Brazil and China [4-6].

In the past, corn was used as feedstock for bioethanol production. After the crisis of grain crops, the feedstock of non-grain crops such as cassava, sugarcane and straw are focused on fermenting ethanol. Lignocelluloses are the most Received date: 2011-01-10 Revised date: 2011-03-09

Foundation Item: National Natural Science Foundation of China (No.20876037) Biography: Zhan Hanhui(1961-)，professor, Ph.D, research fields: environment and bioengineering, China University of Mining and Technology, Xuzhou 221116, China Email:

zhanhhh@263.net

Fig.1 Ethanol production and dosages from 2006 to 2009 in USA,

Brazil and China

abundant renewable natural resources in the world and promising economical sources for ethanol production. Research works in lignocellulosic ethanol production have been carried out in four areas, including pretreatment, hydrolysis, fermentation and product separation. However, the low hydrolysis efficiency, production rates of xylose converting into ethanol and tolerance to ethanol on cell are major barriers to practical application.

The intensive researches on the process of pretreatment, hydrolysis, fermentation and separation were proposed and studied in order to overcome these drawbacks on lignocellulosic ethanol. On the basis of these facts, this review focuses on the recent progress techniques and improvements to existing techniques that have been used to increase hydrolysis efficiency and ethanol yield. Furthermore, some suggestions of developing technologies for future woks are proposed.

1 Processes of lignocellulosic ethanol production

Lignocellulose as feedstock at present faces two major challenges: it is recalcitrant and biodegradation and it contains both pentose and hexose sugars. Research works in