Article

Enzymes with new biochemical properties in the pectinolytic complex produced by Aspergillus niger MIUG 16

Department of Animal Biology, University of Bucharest, București, Bucureşti, Romania
Journal of Biotechnology (Impact Factor: 2.87). 09/2007; 131(2):128-37. DOI: 10.1016/j.jbiotec.2007.06.005
Source: PubMed

ABSTRACT

A comprehensive study on the purification and characterization of pectinolytic enzymes produced by Aspergillus niger MIUG 16 on raw materials solid-state fermentation is reported. Five pectinolytic enzymes were purified using a combination of chromatographic techniques. The properties of these homogenous enzymes were analyzed. The purified enzymes were classified with respect to their biochemical properties and substrate specificity. Among these proteins, one revealed polygalacturonase activity, another appeared to be a pectin methylesterase and three were identified as pectate lyases. The capacity of the fungus A. niger to produce pectate lyases with optimum pH in acidic domain was reported for the first time.

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Available from: Diana Dinu, Apr 27, 2015
    • "Growth on WS revealed that A. niger produced a higher percentage of plant-degrading enzymes in comparison to T. reesei [18]. Furthermore, A. niger strains have been used for the production of a range of plantdegrading enzymes such as pectinases [19, 20] , xylanas- es [21, 22], mannanases [23, 24], and esterases [25, 26]. However, compared to T. reesei, fewer A. niger strains with fine-tuned derepression of carbon regulation are available. "
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    ABSTRACT: Plant-degrading enzymes can be produced by fungi on abundantly available low-cost plant biomass. However, enzymes sets after growth on complex substrates need to be better understood, especially with emphasis on differences between fungal species and the influence of inhibitory compounds in plant substrates, such as monosaccharides. In this study, Aspergillus niger and Trichoderma reesei were evaluated for the production of enzyme sets after growth on two ‘second generation’ substrates: wheat straw and sugarcane bagasse. A. niger and T. reesei produced different sets of (hemi-)cellulolytic enzymes after growth on wheat straw and sugarcane bagasse. This was reflected in an overall strong synergistic effect in releasing sugars during saccharification using A. niger and T. reesei enzyme sets. T. reesei produced less hydrolytic enzymes after growth on non-washed sugarcane bagasse. The sensitivity to non-washed plant substrates was not reduced by using CreA/Cre1 mutants of T. reesei and A. niger with a defective carbon catabolite repression. The importance of removing monosaccharides for producing enzymes was further underlined by the decrease in hydrolytic activities with increased glucose concentrations in WS media. This study showed the importance of removing monosaccharides from the enzyme production media and combining T. reesei and A. niger enzyme sets to improve plant biomass saccharification.
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    • "After incubation for 1 h at 30°C, the reaction was stopped by heating at 100°C for 20 min. Products resulting from sodium polypectate degradation were followed at 235 nm (Dinu et al. 2007; Pissavin et al. 1998). "
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    • "Commercial preparations of pectic enzymes used in food industries are frequently derived from filamentous fungi [1], mainly strains of Aspergillus niger [2] [3] [4]. Species of this group include fungi with asexual reproduction (deuteromycete), included in the class Hyphomycetes, which are characterized by morphological structures typical of the genus Aspergillus. "
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