Enzyme and Microbial Technology 47 (2010) 44–51 Contents lists available at ScienceDirect Enzyme and Microbial Technology journal homepage: www.elsevier.com/locate/emt Improved bio-catalytic conversion by novel immobilization process using cryogel beads to increase solvent production Anuj Tripathi a,b , Haider Sami a,b , Seema R. Jain b , Maria Viloria-Cols b , Natalia Zhuravleva b , Göran Nilsson b , Hans Jungvid b , Ashok Kumar a,b,∗ a Department of Biological Sciences and Bioengineering and Centre for Environmental Sciences and Engineering, Indian Institute of Technology Kanpur, 208016 Kanpur, India b Protista Biotechnology AB, Protista, Kvarngatan 2, P.O. Box 86, 26722 Bjuv, Sweden article info Article history: Received 10 February 2010 Received in revised form 19 March 2010 Accepted 22 March 2010 Keywords: Cryogel beads Immobilization Butanol production Agarose-alginate matrix Fermentation abstract The use of immobilization matrix in bio-processing is a promising approach to immobilize a catalytic strain for production of biomolecules. In this study, a novel immobilization system of agarose-alginate cryogel was developed in the format of beads and characterized to facilitate the effective cell immobiliza- tion followed by enhanced solvent production compared to other immobilization matrix. Cryogel beads showed macroporous internal architecture and nano-range grooves on outer periphery. Study suggests that these grooves facilitate the convective medium transport throughout the cryogel beads in order to eliminate the substrate and product inhibition and also prevent cell leakage. The immobilization study was carried out on a typical anaerobic system of Clostridium acetobutylicum ATCC 824 for butanol pro- duction. The experiment was carried out in three different sets (A, B and C) with varying medium and substrate concentration. The adsorption of cells on agarose-alginate cryogel beads produced 11.79 g/l of butanol and 21.64 g/l total ABE (acetone, butanol and ethanol), while entrapment of cells on agarose- alginate cryogel beads showed high glucose consumption, high butanol and total ABE production that was 92.16%, 14.47 g/l and 27.80 g/l, respectively, which was much higher than the control and other matrices. © 2010 Elsevier Inc. All rights reserved. 1. Introduction Arrays of man-made chemicals in the environment have led an ever-increasing pressure on industrial developments leading to the tremendous deterioration in environmental quality. Biocat- alytic conversion for the production of useful chemicals is the best way to produce particular substance at industrial scale. Though, the use of biomass as the raw material for production of some impor- tant solvents like n-butanol, acetone, ethanol etc, is still appealing and amending environmentally. In contrast, the synthetic pro- cesses have replaced fermentation for commercial production in the early 1960s due to several reasons, of having low produc- tivity, low solvent yield and substantially high recovery cost by distillation process [1,2]. Since then, solvent fermentation could not compete economically with the chemical processes. However, in recent years research has progressed in an attempt to make the solvent fermentation not only environmentally favourable but also economically competitive. In the pharmaceutical and biotech- ∗ Corresponding author at: Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, 208016 Kanpur, India. Tel.: +91 512 2594051; fax: +91 512 2594010. E-mail address: ashokkum@iitk.ac.in (A. Kumar). nology industries, fermentation is an important step of upstream processing. The fermentation process includes large-scale cultiva- tion of microbes or other single cell type, occurring either in aerobic or anaerobic conditions. The industrially important biotechnology processes are generally utilizing microorganism and their applica- tion in the fermentation medium during the process. Such classical fermentations undergo several constrains like, nutritional limita- tions, low cell density, solvent toxicity and batch-mode operations with high down times [3,4]. It has been well recognized that the concentration of microbial cells is prime important during the downstream process to achieve higher volumetric productiv- ity from the fermented medium. Designing of advance bioreactor and its continuous operation with controlled parameters is an important area of research and requires great focus indeed. Many experimental ventures have been carried out on small scale and scaled up but there had been problems of cell leakage through the running fermenter. Therefore, the future research should focus on development of executable microbiological processes with immo- bilized cells and also perform broad research to figure out some of the engineering problems like scale up and diffusion limitations with high cell density. The cell concentration inside the bioreactor can be increased by “cell immobilization technology”. Adsorption and entrapment are two main techniques which have been extensively examined 0141-0229/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.enzmictec.2010.03.009