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Jia J.,Shenzhen Leveking Bio engineering Co. | Yang X.,City University of Hong Kong | Wu Z.,City University of Hong Kong | Zhang Q.,China Institute of Technology | And 5 more authors.
BioMed Research International | Year: 2015

Lipase produced by Aspergillus Niger is widely used in various industries. In this study, extracellular lipase production from an industrial producing strain of A. Niger was improved by medium optimization. The secondary carbon source, nitrogen source, and lipid were found to be the three most influential factors for lipase production by single-factor experiments. According to the statistical approach, the optimum values of three most influential parameters were determined: 10.5 g/L corn starch, 35.4 g/L soybean meal, and 10.9 g/L soybean oil. Using this optimum medium, the best lipase activity was obtained at 2,171 U/mL, which was 16.4% higher than using the initial medium. All these results confirmed the validity of the model. Furthermore, results of the Box-Behnken Design and quadratic models analysis indicated that the carbon to nitrogen (C/N) ratio significantly influenced the enzyme production, which also suggested that more attention should be paid to the C/N ratio for the optimization of enzyme production. © 2015 Jia Jia et al.

Zhou Y.,Wuhan University | Jin Q.,Wuhan University | Gao Z.,Wuhan University | Guo H.,Shenzhen Leveking Bio engineering Co. | And 2 more authors.
RSC Advances | Year: 2014

We have successfully developed an easy and efficient bioprocess for asymmetric organic carbonate synthesis by performing Novozym 435 mediated esterification of DMC and alcohols in this work. Under the optimized conditions (60 °C, molar ratio of alcohol to DMC 1:12), the highest yield of carbonate can reach 95.6%. An additional advantage of the new process is the fact that 90% of the original activity of the enzyme is retained after being recycled nine times. Consequently it has potential as a useful enzyme-catalyzed process for the industrial production of asymmetric organic carbonates. This journal is © The Royal Society of Chemistry 2014.

Liu J.,Wuhan University | Guo H.,Shenzhen Leveking Bio engineering Co. | Zhou Q.,Wuhan University | Wang J.,Shenzhen Leveking Bio engineering Co. | And 5 more authors.
Journal of Molecular Catalysis B: Enzymatic | Year: 2013

Herein, we demonstrated a environmental-friendly biocatalytic route for the synthesis of dimethyl carbonate (DMC), which is the first example to use enzyme in the process. Moreover, immobilization of Penicillium expansum lipase (PEL) using environmentally benign and biodegradable CMC-PVA polymer has significantly enhanced the catalytic activity thus making them an eligible biocatalyst for synthesis of DMC. The biocatalyst revealed high catalytic performance even under ambient pressure and low temperature (conversion of EC to 94%, yield of DMC to 93% and selectivity of DMC to 99%). The immobilized lipase was effectively recycled for four consecutive cycles providing good yields of the desired product. Accompanying with the intense requirement for the green chemicals and process, our work can provide a useful idea for "green and clean" of harmful chemical reaction. © 2013 Elsevier B.V.

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