Effect Of L-Cysteine On Hydrogen Production And Growth Of Ethanoligenens Harbinense YUAN-3

At present the bio-hydrogen production technology has embarked on the road of industrialization.With the growing development and continuous improvement of hydrogen production technology, we pay more attention to improving hydrogen production capacity of the system. Our laboratory had confirmed in prophase that Ethanoligenens B49 manifested different ability of production hydrogen. L-cysteine changed B49 metabolic pathways, greatly promoting hydrogen production capacity of B49. Ethanoligens harbinense YUAN-3 were isolated from the biological hydrogen production reactor of our laboratory, having high efficient of hydrogen production and ability of auto-aggregation. YUAN-3 provides a pattern strain elaborating for production of hydrogen-alcohol metabolism mechanism and mechanism of bacterial auto-aggregation. In actual engineering bioaugmentation by adding YUAN-3 to hygrogen-production system, rapid optimizating community structure, can greatly improved the efficiency of hydrogen production. In this paper, study of the influence of L-cysteine on YUAN-3 studyed and developed for further improving the capacity of hydrogen production system and expanding the scope of YUAN-3 application.This study based on auto-aggregation Ethanoligens harbinens YUAN-3, compared the fermentation process about the availability of L-cysteine in batch culture and continuous culture.In batch culture, L-cysteine concentration inspection is 0 ~ 2.0 g/L. Providing low redox potential to the system in early period , L- cysteine speeded up YUAN-3 fermentation system to be stable and fast entered the growth stage, showing higher capability of hydrogen production and growth.The concentraion 0.8g/L was identified as the best threshold of L-cysteine to promote YUAN-3 capacity of hydrogen production and growth, hydrogen yield being 2.93 molH2/mol-glucose.In the blank test, hydrogen yield is 0.61 molH2/mol glucose only. Excessive concentration, between 0.8 g/L ~ 2.0 g/L, of L-cysteine is favor of YUAN-3 growth instead of hydrogen production. In a certain concentration more than 0.5g/L, L-cysteine enhanced YUAN-3 auto-aggregational ability.Continuous experiments of pure hydrogen-production culture not only have theoretical significance, and have significance guidance on actual project. Bioaugmentation by adding YUAN-3 to hygrogen-production system, solved problem confronting in actual engineering that biomass was difficult to maintain. In continuous culture, we chose the concentration of L-cysteine between 0 ~ 0.2 g/L.Adding 0.2g/L L-cysteine, YUAN-3 fermentation system took a short time to the stable stage of hydrogen-producing, while L-cysteine improved the stability capacity of YUAN-3 fermentation.After 72 hours fermentation, YUAN-3 entered a phase of high-efficiency hydrogen production, hydrogen yield being 1.70 molH2/molglucose. Hydrogen yield reached the maximum 1.88 molH2/molglucose in 144 hours.Cultured in adding no L-cysteine, the maximum hydrogen production of YUAN-3 is 1.81 molH2/molglucose in192 hours.