Isolation and Characterization of a Marine Isolate Bacteria Species for Fermentative Biohydrogen Production Using Casamino Acids as Nitrogen Source

摘要

A mesophilic hydrogen producer was isolated from the marine sediment in Wajiro low tidal flat, Fukuoka Japan and identified as Clostridium butyricum RAK25832 by biochemical tests and 16s rRNA gene sequence analysis. The strain RAK25832 showed the ability for utilize different kinds of carbon sources. Glucose was used as the carbon source, the cumulative hydrogen production at concentration of 10 g/L in was 1262 ml H_2/L. Casamino acids was used as nitrogen source, there was a limitation for the available information for using casamino acids as a nitrogen source for hydrogen production, this study conducted as the first investigation of using casamino acids with the Colstridium butricum sp. Results indicated the preferred concentration was 26.67 g/L this resulted in a maximum cumulative hydrogen production, hydrogen production rate and hydrogen yield of 2505 ml H2/L, 160 ml/hr and 181±8 mmol H_2/mol glucose, respectively. Acetic acid and butyric acid were the main soluble metabolite products giving the possibility of acetate and butyrate type fermentation. Cell density was increased by increasing with increasing casamino acids concentration.