scholarly journals A Novel GH Family 20 β-N-acetylhexosaminidase With Both Chitosanase and Chitinase Activity From Aspergillus oryzae

2021 ◽  
Vol 8 ◽  
Author(s):  
Tianle Qu ◽  
Chunyue Zhang ◽  
Zhen Qin ◽  
Liqiang Fan ◽  
Lihua Jiang ◽  
...  

Aminooligosaccharides possess various biological activities and can exploit wide applications in food, pharmaceutical and cosmetic industries. Commercial aminooligosaccharides are often prepared by the hydrolysis of chitin and chitosan. In this study, a novel GH family 20 β-N-acetylhexosaminidases gene named AoNagase was cloned from Aspergillus oryzae and expressed in Pichia pastoris. The purified AoNagase had maximal activity at pH 5.5 and 65°C. It exhibited good pH stability in the range of pH 6.0–7.5 and at temperatures below 50°C. AoNagase was capable of hydrolyzing not only colloidal chitosan (508.26 U/mg) but also chitin (29.78 U/mg). The kinetic parameters (Km and Vmax) of AoNagase were 1.51 mM, 1106.02 U/mg for chitosan and 0.41 mM, 40.31 U/mg for colloidal chitin. To our knowledge, AoNagase is the first GH family 20 β-N-acetylhexosaminidase capable of hydrolyzing both chitosan and chitin. AoNagase is an endo-type β-N-acetylhexosaminidases and can potentially be used for the manufacturing of aminooligosaccharides.

2020 ◽  
Vol 147 ◽  
pp. 03011
Author(s):  
Eri Pramesti ◽  
Indun Dewi Puspita

Chitinase is an enzyme capable of catalyzing the hydrolysis of chitin. Bacteria is one of the sources for chitinase and the modification process of production are continously developed. Streptomyces sp. is one of Actinomycetes group that shows high activity in hydrolyzing chitin. This study aimed to find the optimal conditions of Streptomyces sp. PB2 for producing chitinase at various colloidal chitin (0.5%, 1%, 1.5%) and inoculum (0.5%, 1%, 1.5%) concentration in the chitin broth medium using Respons Surface Methodology (RSM). The examined parameters included Total Plate Count (CFU/ml) and chitinase activity (U/ml). Chitinase activity was statistically analyzed by MiniTab 17 to obtain a mathematical model, then were validated. The mathematical model of chitinase activity was Y = -0.000075 + 0.00056 K + 0.00067 I, with the optimum colloidal chitin concentration (K) of 1.5% and inoculum concentration (I) of 1.5%. The highest chitinase activity of 0.0019 U/ml in day-2 fermentation. The validation test showed that the mathematical model had a low accuracy with the SSE value of 0.5306. This study shows that colloidal chitin and inoculum concentration are important factors to be optimized. However, further model is needed to be developed for a better estimation of process.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Gaurav Lodhi ◽  
Yon-Suk Kim ◽  
Jin-Woo Hwang ◽  
Se-Kwon Kim ◽  
You-Jin Jeon ◽  
...  

Chitin is a natural polysaccharide of major importance. This biopolymer is synthesized by an enormous number of living organisms; considering the amount of chitin produced annually in the world, it is the most abundant polymer after cellulose. The most important derivative of chitin is chitosan, obtained by partial deacetylation of chitin under alkaline conditions or by enzymatic hydrolysis. Chitin and chitosan are known to have important functional activities but poor solubility makes them difficult to use in food and biomedicinal applications. Chitooligosaccharides (COS) are the degraded products of chitosan or chitin prepared by enzymatic or chemical hydrolysis of chitosan. The greater solubility and low viscosity of COS have attracted the interest of many researchers to utilize COS and their derivatives for various biomedical applications. In light of the recent interest in the biomedical applications of chitin, chitosan, and their derivatives, this review focuses on the preparation and biological activities of chitin, chitosan, COS, and their derivatives.


1980 ◽  
Vol 45 (11) ◽  
pp. 2873-2882
Author(s):  
Vladislav Holba ◽  
Ján Benko

The kinetics of alkaline hydrolysis of succinic acid monomethyl and monopropyl esters were studied in mixed aqueous-nonaqueous media at various temperatures and ionic strengths. The results of measurements are discussed in terms of electrostatic and specific interactions between the reactants and other components of the reaction mixture. The kinetic parameters in the media under study are related to the influence of the cosolvent on the solvation sphere of the reactants.


2021 ◽  
Vol 22 (7) ◽  
pp. 3677
Author(s):  
Zuzana Rosenbergová ◽  
Kristína Kántorová ◽  
Martin Šimkovič ◽  
Albert Breier ◽  
Martin Rebroš

Myrosinase is a plant defence enzyme catalysing the hydrolysis of glucosinolates, a group of plant secondary metabolites, to a range of volatile compounds. One of the products, isothiocyanates, proved to have neuroprotective and chemo-preventive properties, making myrosinase a pharmaceutically interesting enzyme. In this work, extracellular expression of TGG1 myrosinase from Arabidopsis thaliana in the Pichia pastoris KM71H (MutS) strain was upscaled to a 3 L laboratory fermenter for the first time. Fermentation conditions (temperature and pH) were optimised, which resulted in a threefold increase in myrosinase productivity compared to unoptimised fermentation conditions. Dry cell weight increased 1.5-fold, reaching 100.5 g/L without additional glycerol feeding. Overall, a specific productivity of 4.1 U/Lmedium/h was achieved, which was 102.5-fold higher compared to flask cultivations.


In a recent paper a new enzymic relation is recorded. For the enzymic hydrolysis of salicin—by the enzyme which Gabriel Bertrand and the author have named salicinase —it is found that, in an action of fixed duration, the temperature of greatest activity of the ferment is always the same, whatever the dilutions of substrate and of enzyme adopted for the determination. In other words, the duration of the action being constant, the optimum tem­perature of the ferment is independent of the concentration both of the substrate and of the enzyme. The observation is suggestive: if true of one enzyme it may be true of all, and possibly becomes the enunciation of a general law. Herein, for the moment, lies its main interest. In the present paper further experimental evidence for this hypothesis in given, in the case of another hydrolytic enzyme, the maltase of Aspergillus oryzæ (taka-diastase).


2018 ◽  
Vol 46 (1) ◽  
pp. 921-932 ◽  
Author(s):  
Sahar Trabelsi ◽  
Mouna Sahnoun ◽  
Fatma Elgharbi ◽  
Rihab Ameri ◽  
Sameh Ben Mabrouk ◽  
...  

2017 ◽  
Vol 39 (4) ◽  
pp. 423 ◽  
Author(s):  
George Meredite Cunha de Castro ◽  
Norma Maria Barros Benevides ◽  
Maulori Curié Cabral ◽  
Rafael De Souza Miranda ◽  
Enéas Gomes Filho ◽  
...  

 The seaweeds are bio-resource rich in sulfated and neutral polysaccharides. The tropical seaweed species used in this study (Solieria filiformis), after dried, shows 65.8% (w/w) carbohydrate, 9.6% (w/w) protein, 1.7% (w/w) lipid, 7.0% (w/w) moisture and 15.9% (w/w) ash. The dried seaweed was easily hydrolyzed under mild conditions (0.5 M sulfuric acid, 20 min.), generating fermentable monosaccharides with a maximum hydrolysis efficiency of 63.21%. Galactose and glucose present in the hydrolyzed were simultaneously fermented by Saccharomyces cerevisiae when the yeast was acclimated to galactose and cultivated in broth containing only galactose. The kinetic parameters of the fermentation of the seaweed hydrolyzed were Y(P⁄S) = 0.48 ± 0.02 g.g−1, PP = 0.27 ± 0.04 g.L−1.h−1, h = 94.1%, representing a 41% increase in bioethanol productivity. Therefore, S. filiformis was a promising renewable resource of polysaccharides easily hydrolyzed, generating a broth rich in fermentable monosaccharides for ethanol production. 


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