Composition, Aspergillus oryzae

The amino acid compositions of the alpha-amylase from human saliva, hog pancreas, Bacillus suhtilfs, B. stearothermo-philus, Aspergillus oryzae, and malted sorghum have been determined and are shown in Table III. The results show that alpha-amylases from these different sources differ widely in structure. In particular, it is to be noted that cystine and cysteine were not found in the alpha-amylase from B. subtilis. The sequence of amino acids or the three-dimensional structure of any one alpha-amylase is not yet known. The enzyme from A. oryzae differs from the others further, because it is a glycoprotein containing a small proportion of carbo-hydrate. ... 

Fourteen Aspergillus oryzae isolates were evaluated for xylanase and cellulase production on eucalyptus pulp in SSF on two media at two initial pH values. Xylanase production varied between 561 and 4131 lU/g dry matter (DM) of initial substrate (data not shown). Isolate NRRL 447 showed the lowest productivity while strain NRRL 6270 produced the highest results. The xylanase production for the best six strains is shown in Fig.l. Most isolates produced more xylanase when the initial pH of the substrate was higher (pH 8.3). The only exception was isolate 6270 (initial pH of the substrate was pH 7.0). For the best enzyme producer (NRRL 6270), the medium composition had a significant effect on xylanase activity. 

The enzymatic hydrolysis of y-cyclodextrin with Aspergillus oryzae a-amylase was studied by monitoring of the composition of the reaction mixture and by identifying the hydrolysis products with h.p.l.c. method. The product distribution of the enzymatic hydrolysis of y-cyclodextrin after 20, 30, 60 and 90 min reaction time is given in Table I. (In this case maltose could not be separated from the additional components.)... 

Currently, commercial chitin and chitosan are extracted from industrial shellfish processing wastes (shrimp, crab, lobster). The seasonal character of those raw materials and the variability of the composition of the organisms make the process of chitin extraction rather expensive with low reprodudbillty. Moreover, they are subjected to environmental variations that impact on the products supply and quality [14,40,116]. Chitin is extracted from crustacean shells by the use of strong adds and/or bases that can cause deacetylation and depolymerization of chitin [119]. Alternative methods include the use of enzymes or proteolytic microorganisms (e.g.. Pseudomonas malto-philia, Bacillus subtilis. Streptococcus faecium, Aspergillus oryzae) that hydrolyze shellfish proteins and leave the associated chitin intact [119]. 

The acid-stable a-amylase of Aspergillus niger and the acid-labile a-amylase of A. oryzae have been studied.It was shown that in addition to the more stable acid-resistant properties, the a-amylase of A. niger possesses increased thermal stability in comparison with the a-amylase of A. oryzae. The molecular weight of the acid-stable a-amylase is 5.8 x 10 The amino-acid composition, as well as the C- and A -terminal amino-acids of both forms of a-amylases were determined. It was shown that the enzymes each contain one thiol group, which, being bound to Ca ", plays an important role in maintaining the catalytically active conformation of the enzyme. 

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