BIOTECHNOLOGICAL PRODUCTS AND PROCESS ENGINEERING Succinic acid production from orange peel and wheat straw by batch fermentations of Fibrobacter succinogenes S85 Qiang Li & Jose A. Siles & Ian P. Thompson Received: 15 April 2010 / Revised: 30 May 2010 / Accepted: 12 June 2010 / Published online: 20 July 2010 # Springer-Verlag 2010 Abstract Succinic acid is a platform molecule that has recently generated considerable interests. Production of succinate from waste orange peel and wheat straw by consolidated bioprocessing that combines cellulose hydrolysis and sugar fermentation, using a cellulolytic bacterium, Fibrobacter succinogenes S85, was studied. Orange peel contains D-limonene, which is a well-known antibacterial agent. Its effects on batch cultures of F. succinogenes S85 were examined. The minimal concentrations of limonene found to inhibit succinate and acetate generation and bacterial growth were 0.01%, 0.1%, and 0.06% (v/v), respectively. Both pre-treated orange peel by steam distillation to remove D- limonene and intact wheat straw were used as feedstocks. Increasing the substrate concentrations of both feedstocks, from 5 to 60 g/L, elevated succinate concentration and productivity but lowered the yield. In addition, pre-treated orange peel generated greater succinate productivities than wheat straw but had similar resultant titres. The greatest succinate titres were 1.9 and 2.0 g/L for pre-treated orange peel and wheat straw, respectively. This work demonstrated that agricultural waste such as wheat straw and orange peel can be biotransformed to succinic acid by a one-step consolidated bioprocessing. Measures to increase fermentation efficiency are also discussed. Keywords Succinic acid . Orange peel . Wheat straw . Fibrobacter succinogenes . Bio-refinery Introduction With increasing concerns regarding the use of fossil resources, there is growing interest in cost-effective and sustained alternative routes of sourcing essential commodities (Hansen et al. 2005; Webb et al. 2004). Lignocellulosic biomass is particularly well-suited for energy applications because of its large-scale availability, low cost, and environmentally benign production (Lynd et al. 1999). Research has focused mostly on the conversion of this resource to fuel ethanol, but interest has recent grown in developing biological technologies for the production of organic acids such as succinic acid, which is predicted to be one of the future platform chemicals that can be derived from renewable resources (Bechthold et al. 2008; Gokarn et al. 1997). This acid has a broad range of industrial applications such as source of food, pharmaceuticals, surfactants, detergent extenders, antifoam agents, ion chelators, and in the manufacture of resins, polymers, paints, cosmetics, and inks (Isar et al. 2006). It can also be exploited for the generation of several industrially important chemicals such as adipic acid, 1,4-butanediol, tetrahydrofuran, N-methyl pyrrolidinone, 2- pyrrolidinone, succinate salts, gamma-butyrolactone, poly- Q. Li Department of Biochemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK J. A. Siles Departamento de Química Inorgánica e Ingeniería Química, Facultad de Ciencias, Universidad de Córdoba, Campus Universitario de Rabanales, Edificio Marie Curie (C-3), Ctra. Madrid-Cádiz, km 396, 14071 Córdoba, Spain I. P. Thompson (*) Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK e-mail: ian.thompson@eng.ox.ac.uk Appl Microbiol Biotechnol (2010) 88:671–678 DOI 10.1007/s00253-010-2726-9