RESUMO
Fermentation with acetogens can be affected by cultivation gas phase, but to date, there is not enough evidence on that matter for Clostridium thermocellum and Moorella thermoacetica. In this work, the effects of sparged CO2 as well as sparged and non-sparged N2 on these microorganisms were studied using glucose and cellobiose as substrates. It was revealed that sparged CO2 and non-sparged N2 supported growth and acetic acid production by C. thermocellum and M. thermoacetica, while sparged N2 inhibited both of the microorganisms. Notably, part of the sparged CO2 was fermented by the co-culture system and contributed to an overestimation of the products from the actual substrate as well as an erring material balance. The best condition for the co-culture was concluded to be N2 without sparging. These results demonstrate the importance of cultivation conditions for efficient fermentation by anaerobic clostridia species.
Assuntos
Ácido Acético/metabolismo , Clostridium thermocellum/metabolismo , Fermentação , Gases , Moorella/metabolismo , Anaerobiose , Dióxido de Carbono/farmacologia , Celobiose/farmacologia , Clostridium thermocellum/efeitos dos fármacos , Clostridium thermocellum/crescimento & desenvolvimento , Técnicas de Cocultura , Glucose/farmacologia , Hidrogênio , Moorella/efeitos dos fármacos , Moorella/crescimento & desenvolvimento , Nitrogênio/farmacologiaRESUMO
Biomass pretreatment for depolymerizing lignocellulosics to fermentable sugars has been studied for nearly 200 years. Researches have aimed at high sugar production with minimal degradation to inhibitory compounds. Chemical, physico-chemical and biochemical conversions are the most promising technologies. This article reviews the advances and current trends in the pretreatment of lignocellulosics for a prosperous biorefinery.
