Yv. Burtseva et al., Enzymes of carbohydrate metabolism of mycelial fungi from marine environments. beta-1,3-glucanase of the marine fungus Chaetomium indicum, BIOCHEM-MOS, 65(10), 2000, pp. 1175-1183
Thirty samples of fungi belonging to 17 species living in marine environmen
ts were studied for their ability to produce extracellular enzymes. In the
culture fluids, a variety of glycosidases (beta -glucosidases, N-acetyl-bet
a -glucosaminidase, beta -galactosidases, and alpha -mannosidases) and gluc
anases (amylases and beta -1,3-glucanases) were found. Several cultures wer
e found that could be used as efficient producers of either individual enzy
mes or a whole complement of enzymes degrading carbohydrate-containing comp
ounds. Optimal growth conditions for the fungus Chaetomium indicum and beta
-1,S-glucanase biosynthesis were developed. beta -1,3-Glucanase was isolat
ed by a combination of ion-exchange chromatography, ultrafiltration, and ge
l chromatography. The molecular mass of the enzyme determined by gel-filtra
tion was 54 kD. The enzyme was stable at temperatures below 50 degreesC, ha
d a temperature optimum for activity at 60 degreesC, and retained activity
between pH 4.5 and 7.5. The pH dependence of the beta -1,3-glucanase activi
ty showed two maxima, at pH 4.4 and 5.6; this suggested the existence of tw
o forms of the enzyme. Analysis of the products of enzymatic hydrolysis of
laminaran, transglycosylating ability, and the effect of a specific natural
inhibitor indicates that both forms are exo-beta -1,3-glucanases.