Search

BACKGROUND Mycelia pellet has been exploited as a biological carrier for whole-cell immobilization due to its unique structural characteristics. An innovative two-species whole-cell immobilization system was developed initially, which was achieved simply by inoculating the marine-derived fungus Pestalotiopsis sp. J63 spores into culture medium containing another fungus Penicillium janthinellum P1 pre-grown mycelia pellets for 2 days. RESULTS The resulting co-immobilization system exhibited stronger biocatalytic activity, broader spectrum of substrates and remained more stable in media when subjected to hostile environment than free mycelia. In order to examine the potential function and prospects of this co-immobilization system, the treatment of paper mill effluent was applied as a practical example. Numerous insoluble fine fibers in the wastewater were successfully and rapidly biodegraded and removed using this novel co-immobilization system. CONCLUSION Overall, the present study offers a simple and reproducible way to architect a two-species whole-cell immobilization system, which is highly promising for biochemical and industrial processes. © 2013 Society of Chemical Industry

BACKGROUND: A process combining biocatalytic reaction and cell activity regeneration was designed for the asymmetric reduction of 3-oxo ester. By immobilizing resting baker's yeast (Saccharomyces cerevisiae) in calcium alginate beads, the high yield and long catalyst life were achieved in the aqueous phase in this process with methyl acetoacetate (MAA) as the model substrate. RESULTS: Two combined fixed-bed reactors were able to work steadily for at least 16 days. The activity of immobilized baker's yeast could be retained by re-culture with culture medium regularly. The re-culture time for bead reactivation was optimized to be 30 h. High yield (about 80%) and high enantiomeric excess (>95%) were maintained after 12 batches of asymmetric reduction. The immobilized beads retained their original shapes even after a long reaction time in the fixed-bed reactor, while the beads broke after reaction of five batches in a flask. CONCLUSION: The combined process of biocatalysis and cell activity regeneration was successfully achieved in the asymmetric reduction and decreased the breakage of beads as well as increased the efficiency of catalyst. Copyright © 2008 Society of Chemical Industry

BACKGROUND:Arthrobacter simplex cells immobilised in sodium cellulose sulfate/poly-dimethyl-diallyl-ammonium chloride microcapsules were used for the microbial dehydrogenation of 11α-hydroxy-16α,17-epoxyprogesterone to 11α-hydroxy-16α,17α-epoxypregn-1,4-diene-3,20-dione in an aqueous/organic solvent two-liquid-phase system, which is a key reaction in the production of glucocorticoid pharmaceuticals. The aim of the study was to establish a suitable aqueous/organic solvent two-liquid-phase system for performing semi-continuous production in an airlift loop reactor by encapsulated A. simplex cells with the addition of suitable surfactants to achieve a higher yield of the product. RESULTS:n-Hexane was selected as the most suitable organic solvent. In optimised Tween-80 emulsion feed mode the conversion in the airlift loop reactor was as high as 97.54% when the time of reaction was 2 h, and the reaction time was greatly shortened. In semi-continuous production the cultivation with immobilised cells was carried out for five batches in total. The conversion in each batch was above 95% and the enzymatic activity still remained quite high after five batches of biotransformation. CONCLUSION: The results showed that performing the conversion by this method shortened the reaction time and increased the productivity, thus demonstrating the great potential of the method for the dehydrogenation of 11α-hydroxy-16α,17-epoxyprogesterone. Copyright © 2008 Society of Chemical Industry