Metabolic selectivity and growth of Clostridium thermocellum in continuous culture under elevated hydrostatic pressure

被引:58
作者
Bothun, GD
Knutson, BL [1 ]
Berberich, JA
Strobel, HJ
Nokes, SE
机构
[1] Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA
[2] Univ Kentucky, Dept Anim Sci, Lexington, KY 40546 USA
[3] Univ Kentucky, Dept Biosyst & Agr Engn, Lexington, KY 40546 USA
基金
美国国家科学基金会;
关键词
D O I
10.1007/s00253-004-1554-1
中图分类号
Q81 [生物工程学(生物技术)]; Q93 [微生物学];
学科分类号
071005 ; 0836 ; 090102 ; 100705 ;
摘要
The continuous culture of Clostridium thermocellum, a thermophilic bacterium capable of producing ethanol from cellulosic material, is demonstrated at elevated hydrostatic pressure (7.0 MPa, 17.3 MPa) and compared with cultures at atmospheric pressure. A commercial limitation of ethanol production by C. thermocellum is low ethanol yield due to the formation of organic acids (acetate, lactate). At elevated hydrostatic pressure, ethanol:acetate (E/A) ratios increased >10(2) relative to atmospheric pressure. Cell growth was inhibited by approximately 40% and 60% for incubations at 7.0 MPa and 17.3 MPa, respectively, relative to continuous culture at atmospheric pressure. A decrease in the theoretical maximum growth yield and an increase in the maintenance coefficient indicated that more cellobiose and ATP are channeled towards maintaining cellular function in pressurized cultures. Shifts in product selectivity toward ethanol are consistent with previous observations of hydrostatic pressure effects in batch cultures. The results are partially attributed to the increasing concentration of dissolved product gases (H-2, CO2) with increasing pressure; and they highlight the utility of continuous culture experiments for the quantification of the complex role of dissolved gas and pressure effects on metabolic activity.
引用
收藏
页码:149 / 157
页数:9
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