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Fermentation of biomass‐generated producer gas to ethanol
Author(s) -
Datar Rohit P.,
Shenkman Rustin M.,
Cateni Bruno G.,
Huhnke Raymond L.,
Lewis Randy S.
Publication year - 2004
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20071
Subject(s) - biomass (ecology) , biofuel , fermentation , ethanol fuel , producer gas , syngas , chemistry , renewable energy , pulp and paper industry , ethanol fermentation , bioenergy , natural gas , ethanol , waste management , food science , fuel gas , hydrogen , agronomy , combustion , organic chemistry , biology , ecology , engineering
The development of low‐cost, sustainable, and renewable energy sources has been a major focus since the 1970s. Fuel‐grade ethanol is one energy source that has great potential for being generated from biomass. The demonstration of the fermentation of biomass‐generated producer gas to ethanol is the major focus of this article in addition to assessing the effects of producer gas on the fermentation process. In this work, producer gas (primarily CO, CO 2 , CH 4 , H 2 , and N 2 ) was generated from switchgrass via gasification. The fluidized‐bed gasifier generated gas with a composition of 56.8% N 2 , 14.7% CO, 16.5% CO 2 , 4.4% H 2 , and 4.2% CH 4 . The producer gas was utilized in a 4‐L bioreactor to generate ethanol and other products via fermentation using a novel clostridial bacterium. The effects of biomass‐generated producer gas on cell concentration, hydrogen uptake, and acid/alcohol production are shown in comparison with “clean” bottled gases of similar compositions for CO, CO 2 , and H 2 . The successful implementation of generating producer gas from biomass and then fermenting the producer gas to ethanol was demonstrated. Several key findings following the introduction of producer gas included: (1) the cells stopped growing but were still viable, (2) ethanol was primarily produced once the cells stopped growing (ethanol is nongrowth associated), (3) H 2 utilization stopped, and (4) cells began growing again if “clean” bottled gases were introduced following exposure to the producer gas. © 2004 Wiley Periodicals, Inc.