| Effect of Substrate Concentration on Biohydrogen Production by Clostridium manihotivorum CT4 in Batch Culture Saengmany Phommakod1; Pawinee Chaiprasert2; Warinthorn Songkasiri3; 1SCHOOL OF BIORESOURCES AND TECHNOLOGY, KING MONGKUT'S UNIVERSITY OF TECHNOLOGY THONBURI, Bangkhuntian, Thailand; 2SCHOOL OF BIORESOURCES AND TECHNOLOGY, KING MONGKUT'S UNIVERSITY OF TEACHNOLOGY THONBURI, Bangkhuntian, Thailand; 3NATIONAL CENTER FOR GENETIC ENGINEERING AND BIOTECHNOLOGY (BIOTEC), NATIONAL SCIENCE AND TECHNOLOGY DEVELOPMENT AGENCY (NSTDA), Pathum Thani, Thailand; PAPER: 468/Energy/Regular (Oral) SCHEDULED: 16:45/Mon. 28 Nov. 2022/Game ABSTRACT: Biohydrogen has the potential to replace current hydrogen production technologies relying heavily on fossil fuels [1]. Dark fermentation has an excellent capability for evolution as a practical biohydrogen production because of high hydrogen yields [2]. The substrate concentration is one significant factor in hydrogen production. This study examined substrate concentration's influence on fermentative hydrogen production by Clostridium manihotivorum CT4. This microorganism was isolated from the cassava pulp, solid waste of the cassava starch factory [3]. Experiments were conducted in batch tests using glucose as a substrate varying between 0 to 25 g/L at 37 ºC and an initial pH of 7.0. Experimental results showed that during dark fermentation, the hydrogen production potential and hydrogen production rate increased following the increase in substrate concentration between 0 to 25 g/L glucose. In our batch assays, the lower glucose concentration that provided the highest hydrogen production yield and substrate degradation efficiency was 41.5 mL/g glucose and 96.2%, respectively, at the substrate concentration of 5 g/L glucose due to lower substrate concentration diminishes volatile fatty acids (VFAs) concentrations and further affecting the hydrogen production yield. An increase in the initial substrate concentration supplemented in this experiment caused a reduction in substrate utilization rate and hydrogen production yield. Because of the higher glucose concentration might have the accumulation of the products from glucose utilization, such as VFAs, causing the pH to drop to lower than 5.5 in the culture to become acidic and unsuitable for microbial growth [4]. These results will be useful for optimizing the substrate concentration and controlling the fermentative biohydrogen production process by using C. manihotivorum CT4 directly from glucose under these conditions. References: [1] L. Singh, Z.A. Wahid. J Ind Eng Chem. 21 (2015) 70-80. [2] P.C. Hallenbeck, D. Ghosh. Trends Biotechnol. 27 (2009) 287-297 [3] P. Cheawchanlertfa, S. Sutheeworapong, P. Jenjaroenpun, T. Wongsurawat, I. Nookaew, S. Cheevadhanarak. PeerJ. 8 (2020) 1-28. [4] D. Levin, R. Islam, N. Cicek, R. Sparling. Int. J. Hydrog. Energy. 31 (2006) 1496-1503. |
