• 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • br Conflict of interest statement


    Conflict of interest statement
    References and recommended reading Papers of particular interest, published within the period of review, have been highlighted as:
    Acknowledgements We acknowledge financial support by the Swiss State Secretariat for Education, Research and Innovation (Federal project contributions 2017–2020, P-14: Innovation in Biocatalysis) and by Innosuisse—Swiss Innovation Agency (Grant No. 28385.1 PFLS-LS).
    Introduction An enzyme preparation consisting of equal parts of crude extracts from the fungi Chrysoporthe cubensis (grown in medium containing wheat bran via solid state fermentation) and Penicillium pinophilum (cultivated under submerged fermentation with elephant grass) showed enhancement in lignocellulose hydrolysis when compared to preparations of the individual extracts [1]. C. cubensis produced a crude enzyme extract with significant β-glucosidase activity, while the extract from P. pinophilum contained higher activities of filter paper (total cellulase) hydrolyzing and endoglucanase activities. Combined, these preparations have the potential to reduce cost by improving efficiency of hydrolysis [2], [3]. Phenolic compounds generated during GW311616 hydrochloride pretreatment inhibit and/or deactivate cellulolytic/hemicellulolytic enzymes as well as the viability and fermentative capacity of yeast and bacteria [4], [5], [6], [7], [8], [9], [10], [11], [12], [13]. Phenolic compounds cause changes in protein conformation leading to enzyme inactivation, although the exact mechanisms of inhibition are not fully understood [7]. This paper provides significant experimental data that shows enzymes from C. cubensis:P. pinophilum are more tolerant to phenolic inhibitors than enzymes from Trichoderma reesei and Aspergillus niger, microorganisms that represent a major source of commercially available cellulases and hemicellulases [8], [9], [11], [12], [13]. Laccase is shown to play a role in protecting hemicellulases from the effects of lignin-derived phenols.
    Materials and methods
    Results and discussion
    Conclusions Phenols deactivated cellulolytic and hemicellulolytic enzymes from C. cubensis:P. pinophilum mixtures. Oligomeric phenol (tannic acid) caused greater deactivation than monomeric phenols tested at the same concentrations and had a major impact on decreasing enzyme activity, regardless of the source of the enzyme. Even though the observed deactivation effect of selected monomeric and oligomeric phenols was significant for most of the enzyme activities tested, with exception of β-mannosidase activity, cellulolytic enzymes in the mixture from C. cubensis:P. pinophilum were more resistant to deactivation than equivalent cellulolytic enzymes from T. reesei and A. niger and have commercial potential in this regard. The presence of laccase activity mitigated deactivation due to phenols on xylanase and other hemicellulases, thus helping these xylan hydrolyzing enzymes to display a tolerance to phenolic inhibitors/deactivating compounds.
    Author agreement
    Acknowledgments We thank Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for the financial support and Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico (CNPq) for providing scholarships. This work was also supported by Hatch Act 10677, 10646, Purdue University Agricultural Research Programs and the Department of Agricultural and Biological Engineering, and CAPES (PDSE – Process 000218/2014-06, Process 012981/2013-03), Brazil.
    Introduction Prodrugs are the inactive derivatives of drug molecules, which can be used to improve drugs\' stability, water-solubility, selectivity, etc. [1], [2], [3], [4], [5], [6], [7], [8], [9]. The key step for performing prodrug therapy is that the reversible prodrugs can be effectively activated when and where they are needed. Prodrug activation by enzymes is a common method for converting prodrugs into effective drugs [2], [10], [11], [12], [13], [14], [15]. In order to realize selective prodrug activation and supplement the lack of endogenous enzymes for matching different types of prodrugs, introduction of the exogenous natural enzymes to target cells is needed. This usually depends on gene transfection or antibody-enzyme delivery [16], [17], [18], [19]. However, this process is complicated and great skills are often required. As a result, the prodrug therapy based on natural enzymes needs to be further improved, especially with the development of enzyme mimics.