Gasification is a process by which lignocellulosic substrates are partially oxidized under high temperatures to liberate syngas which can readily be converted to ethanol by either inorganic or biocatalytic conversions. Biological production of fuel from syngas offers several advantages over catalytic techniques including conversion occurring under mild temperatures and pressures than catalytic reactors, higher reaction specificity of enzymes, reduced costs and no stoichiometric limitations.
The process includes pumping of the gas mixture into the bioreactor where microbes under anaerobic condition will catalytically reduce the oxides of carbon into hydrides as ethanol and subsequently resolved form the reactor mix by distillation and repeated as cycles. Several acetogenic microbes are capable of metabolizing syngas into ethanol. Two of the most promising strains are Butyribacterium methylotrophicum and Clostridium ljungdahlii. Eventhough advantages have been pointed, constraints including contamination, strain performance, technical optimization for the sustained maintenance of pure, viable microbial cultures and stable anaerobic incubation to avoid lethal oxygenation toxicity to producer organisms.
