Identification of by-products in hydrogen producing bacteria; Rhodobacter sphaeroides OU 001 grown in the waste water of a sugar refinery

Rhodobacter sphaeroides O.U.001 is able to produce hydrogen anaerobically u pon illumination. The cells were screened for the presence of valuable by-p roducts such as poly-e-hydroxy (PHB) butyric acid aiming to improve the fea sibility of the system. Also waste water from a sugar refinery was used for bacterial growth to further increase the feasibility. Under aerobic condit ions the standard growth media containing L-malic acid and sodium glutamate in 7.5/10 and 15/2 molar ratios and a medium containing 30% waste water fr om sugar refinery were used, In this case the maximum concentration of PHB produced were approximately 0.2 g l(-1) in both of the standard media where as it was 0.3 g l(-1) in medium containing 30% waste water. By using the me dium containing 30% waste water, PHB and hydrogen productions were determin ed under anaerobic conditions. The maximum concentration of PHB produced wa s around 0.5 g l(-1) and the amount of gas collected was 35 mi in 108 h. Fr om these results it can be concluded that PHB can be collected during hydro gen production. The use of waste water from sugar refinery increased the yi eld. (C) 1999 Elsevier Science B.V. All rights reserved.