Production of branched-chain alcohols by recombinant Ralstonia eutropha in fed-batch cultivation
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- 作者：Qiang Fei ; Christopher J. Brigham ; Jingnan Lu ; Rongzhan Fu ; Anthony J. Sinskey
- 关键词：Biofuel ; Isobutanol ; 3-Methyl-1-butanol (isoamyl alcohol) ; Recombinant Ralstonia eutropha ; pH-Stat control ; Two-stage fed-batch culture
- 刊名：Biomass and Bioenergy
- 出版年：2013
- 出版时间：September, 2013
- 年：2013
- 卷：56
- 期：Complete
- 页码：334-341
- 全文大小：793 K
文摘
Branched-chain alcohols are considered promising green energy sources due to their compatibility with existing infrastructure and their high energy density. We utilized a strain of Ralstonia eutropha capable of producing branched-chain alcohols and examined its production in flask cultures. In order to increase isobutanol and 3-methyl-1-butanol (isoamyl alcohol) productivity in the engineered strain, batch, fed-batch, and two-stage fed-batch cultures were carried out in this work. The effects of nitrogen source concentration on branched-chain alcohol production were investigated under four different initial concentrations in fermenters. A maximum 380?g?m?3 of branched-chain alcohol production was observed with 2?kg?m?3 initial NH4Cl concentration in batch cultures. A pH-stat control strategy was utilized to investigate the optimum carbon source amount fed during fed-batch cultures for higher cell density. In cultures of R. eutropha strains that did not produce polyhydroxyalkanoate or branched-chain alcohols, a maximum cell dry weight of 36?kg?m?3 was observed using a fed-batch strategy, when 10?kg?m?3 carbon source was fed into culture medium. Finally, a total branched-chain alcohol titer of 790?g?m?3, the highest branched-chain alcohol yield of 0.03?g?g?1, and the maximum branched-chain alcohol productivity of 8.23?g?m?3?h?1 were obtained from the engineered strain Re2410/pJL26 in a two-stage fed-batch culture system with pH-stat control. Isobutanol made up over 95 % (mass fraction) of the total branched-chain alcohols titer produced in this study.