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      Stereoselective biotransformation of racemic mandelic acid using immobilized laccase and (S)-mandelate dehydrogenase

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          Abstract

          Objectives

          (S)-Mandelate dehydrogenase (SMDH) and laccase were immobilized on chitosan. The bi-enzymatic system with immobilized SMDH and immobilized laccase was taken to catalyze the stereoselective transformation of racemic mandelic acid and (R)-mandelic acid was obtained from its racemic mixture.

          Results

          Characteristics of the immobilized enzymes were valuated. The optimum pH and temperature of the immobilized SMDH were found to be pH 3.4 and 45 °C, and these of the immobilized laccase were about pH 6.0 and 55 °C, respectively. The K m value of the immobilized SMDH for racemic mandelic acid was 0.27 mM and that of the immobilized laccase for ferrocyanide was 0.99 mM. The thermal and storage stabilities of these enzymes were improved with immobilization. The enantiomeric purity of the bi-enzymatically produced (R)-mandelic acid was determined to be over 99%.

          Conclusion

          The immobilized bi-enzymatic system for the stereoselective transformation of racemic mandelic acid showed higher productivity, faster reaction velocity, and more stable catalytic ability.

          Graphical abstract

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          Most cited references26

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          Modifying enzyme activity and selectivity by immobilization.

          Rafael C Rodrigues, Claudia Ortiz, Angel Berenguer-Murcia … (2013)
          Immobilization of enzymes may produce alterations in their observed activity, specificity or selectivity. Although in many cases an impoverishment of the enzyme properties is observed upon immobilization (caused by the distortion of the enzyme due to the interaction with the support) in some instances such properties may be enhanced by this immobilization. These alterations in enzyme properties are sometimes associated with changes in the enzyme structure. Occasionally, these variations will be positive. For example, they may be related to the stabilization of a hyperactivated form of the enzyme, like in the case of lipases immobilized on hydrophobic supports via interfacial activation. In some other instances, these improvements will be just a consequence of random modifications in the enzyme properties that in some reactions will be positive while in others may be negative. For this reason, the preparation of a library of biocatalysts as broad as possible may be a key turning point to find an immobilized biocatalyst with improved properties when compared to the free enzyme. Immobilized enzymes will be dispersed on the support surface and aggregation will no longer be possible, while the free enzyme may suffer aggregation, which greatly decreases enzyme activity. Moreover, enzyme rigidification may lead to preservation of the enzyme properties under drastic conditions in which the enzyme tends to become distorted thus decreasing its activity. Furthermore, immobilization of enzymes on a support, mainly on a porous support, may in many cases also have a positive impact on the observed enzyme behavior, not really related to structural changes. For example, the promotion of diffusional problems (e.g., pH gradients, substrate or product gradients), partition (towards or away from the enzyme environment, for substrate or products), or the blocking of some areas (e.g., reducing inhibitions) may greatly improve enzyme performance. Thus, in this tutorial review, we will try to list and explain some of the main reasons that may produce an improvement in enzyme activity, specificity or selectivity, either real or apparent, due to immobilization.
          Article 0 comments Cited 374 times – based on 0 reviews     Review now
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            The biological significance of substrate inhibition: a mechanism with diverse functions.

            John C. Reed, A Steger-Lieb, H. Frederik Nijhout (2010)
            Many enzymes are inhibited by their own substrates, leading to velocity curves that rise to a maximum and then descend as the substrate concentration increases. Substrate inhibition is often regarded as a biochemical oddity and experimental annoyance. We show, using several case studies, that substrate inhibition often has important biological functions. In each case we discuss, the biological significance is different. Substrate inhibition of tyrosine hydroxylase results in a steady synthesis of dopamine despite large fluctuations in tyrosine due to meals. Substrate inhibition of acetylcholinesterase enhances the neural signal and allows rapid signal termination. Substrate inhibition of phosphofructokinase ensures that resources are not devoted to manufacturing ATP when it is plentiful. In folate metabolism, substrate inhibition maintains reactions rates in the face of substantial folate deprivation. Substrate inhibition of DNA methyltransferase serves to faithfully copy DNA methylation patterns when cells divide while preventing de novo methylation of methyl-free promoter regions.
            Article 0 comments Cited 77 times – based on 0 reviews     Review now
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              Immobilization of Pycnoporus sanguineus laccase on magnetic chitosan microspheres

              De-Sheng Jiang, Sheng-Ya Long, Jun-Biao Huang … (2005)
              Article 0 comments Cited 60 times – based on 0 reviews     Review now
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                Author and article information

                Contributors
                Xing Chen: 13770319302@139.com
                Chengli Yang: bioedu@sina.com
                Peng Wang: educell@163.com
                Xuan Zhang: XuanZhang123njust@163.com
                Bingxin Bao: njust@163.com
                Dali Li: lidali@njust.edu.cn
                Ruofu Shi: edubio@163.com
                Journal
                Journal ID (nlm-ta): Bioresour Bioprocess
                Journal ID (iso-abbrev): Bioresour Bioprocess
                Title: Bioresources and Bioprocessing
                Publisher: Springer Berlin Heidelberg (Berlin/Heidelberg )
                ISSN (Electronic): 2197-4365
                Publication date (Electronic): 3 January 2017
                Publication date PMC-release: 3 January 2017
                Publication date (Print): 2017
                Volume: 4
                Issue: 1
                Electronic Location Identifier: 2
                Affiliations
                Department of Bioengineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, 210094 People’s Republic of China
                Article
                Publisher ID: 135
                DOI: 10.1186/s40643-016-0135-3
                PMC ID: 5236080
                PubMed ID: 28133593
                SO-VID: 868bd642-5f0e-4724-aa5f-13fb8bdbecc4
                Copyright © © The Author(s) 2017
                License:

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

                History
                Date received : 24 August 2016
                Date revision received : 26 December 2016
                Date accepted : 27 December 2016
                Categories
                Subject: Research
                Custom metadata
                issue-copyright-statement © The Author(s) 2017

                Keywords: biocatalysis,(s)-mandelate dehydrogenase,laccase,immobilization,chitosan,bi-enzymatic system
                Data availability:
                Keywords: biocatalysis, (s)-mandelate dehydrogenase, laccase, immobilization, chitosan, bi-enzymatic system

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