Exploitation of novel wild type solventogenic strains for butanol production

Fengxue Xin,Weiliang Dong,Wei Yan,Hao Wu,Jie Zhou,Jiangfeng Ma,Min Jiang,Wenming Zhang

doi:10.1186/s13068-018-1252-3

Abstract

Butanol has been regarded as an important bulk chemical and advanced biofuel; however, large scaling butanol production by solventogenic Clostridium sp. is still not economically feasible due to the high cost of substrates, low butanol titer and yield caused by the toxicity of butanol and formation of by-products. Renewed interests in biobutanol as biofuel and rapid development in genetic tools have spurred technological advances to strain modifications. Comprehensive reviews regarding these aspects have been reported elsewhere in detail. Meanwhile, more wild type butanol producers with unique properties were also isolated and characterized. However, few reviews addressed these discoveries of novel wild type solventogenic Clostridium sp. strains. Accordingly, this review aims to comprehensively summarize the most recent advances on wild type butanol producers in terms of fermentation patterns, substrate utilization et al. Future perspectives using these native ones as chassis for genetic modification were also discussed.

Highlights

Biobutanol has gained great attention as a liquid transportation fuel owning to its similar physical and chemical properties to gasoline in addition to being renewable [1, 2]
Conclusions and future perspectives Large scaling biobutanol production through acetone– butanol–ethanol (ABE) fermentation process remains a great challenge, primarily due to the low butanol titer caused by the toxicity of butanol to cells and low yield caused by the formation of by products, mainly acetone [56]
The rapid development of genetic tools for molecular characterization of complex phenotypes has led to numerous new insights into butanol tolerance, and various solventogenic Clostridium sp. have been genetically engineered to improve the butanol tolerance and final butanol titer

Summary

Introduction

Biobutanol has gained great attention as a liquid transportation fuel owning to its similar physical and chemical properties to gasoline in addition to being renewable [1, 2]. Strains is an industrially established process, and large scaling biobutanol production has been applied for more than 100 years [3,4,5] It is still not economically feasible due to several obstacles, such as the high cost of traditional feedstocks (starchy based materials), low butanol titer caused by the lipophilic property of butanol and low butanol yield caused by the formation of side products, mainly acetone [6,7,8]. C. acetobutylicum ATCC 824 and C. beijerinckii NCIMB 8052 are two most wellknown butanol-producing species Genetic modification of these strains has been comprehensively investigated to improve their fermentation efficiencies, including the improvement of butanol tolerance, simultaneous utilization of glucose and xylose, elimination of acetone production and conversion of acetone into isopropanol [10,11,12,13]. The disruption of acetoacetate decarboxylase gene (adc) in C. acetobutylicum could minimize the acetone formation; butanol production of the recombinant strain was affected

Objectives

Findings

Conclusion