Biohydrogen production from palm oil mill effluent using immobilized mixed culture

Cell immobilization techniques were adopted to bio-hydrogen production using immobilized anaerobic sludge as the seed culture. Palm oil mill effluent (POME) was used as the substrate carbon source. It was found that with a POME concentration of 20 g COD/l in the feed, the suspended-cell containing reactor was able to produce hydrogen at an optimal rate of 0.3481 l H-2/(l POME h) at HRT 6 h. However, the immobilized-cell containing reactor exhibited a better hydrogen production rate of 0.589 l H-2/(l POME h), which occurred at HRT 2 h. When the immobilized-cell containing reactor was scaled up to 5 l, the hydrogen production rate was 0.500-0.588 l H-2/(l POME h) for HRT 2-10 h, but after a thermal treatment (60 degrees C, 1 h) the rate increase to 0.632 l H-2/(l POME h) at HRT 2 h. The main soluble metabolites were butyric acid and acetic acid, followed by propionic acid and ethanol. (c) 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.