担子菌による植物組織の崩壊 : (第2報)粗酵素の各種多糖類分解活性について

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Two Basidiomycetes strains, Fomitopsis cytisina and Irpex lacreus, were cultivated in a 30 l jar fermenter and crude enzyme preparations were prepared from the culture broth.Macerating, pectolytic, and celluloytic activities of these two preparations were compared with those of some enzyme preparations on the market (Macerozyme and Cellulase"Onozuka"P-500). It was found that all activities tested of the two preparations per weight of crude enzyme powder were 2 to 5 times higher than those of commercial enzyme preparations.Next, some enzymological properties of these two preparations were investigated.The optimum pH value of the enzyme preparation of F. cytisina for the maceration of potato-tuber was about 5.0,whereas that of I. lacteus was more acidic (4.0-5.0).The enzyme obtained from F. cytisina was almost stable within the pH range of 4.0-7.0,but than obtained from I. lacteus was stable within a wider pH range below 7.0.The optimum temperatures for the potato-tuber maceration of these two preparations were around 45-50 ℃. The macerating activity of these enzymes was reduced to almost nothing by heat treatment at 60 ℃ for 10 min.From the investigation of the pectolytic activity of these two preparations, it was revealed that these preparations did not contain pectin esterase (PE) and pectin and/or pectic acid transe-liminase (PTE), but did contain polygalacturonase (PG) or polymethylgalacturonase (PMG).Moreover, these preparations were able to hydrolyze pectin more easily than pectic acid.The enzyme preparation of I. lacteus is quite different from that of F. cytisina in the point than the former contained a cellulolytic enzyme with a high activity for the decomposition of filter paper, a β-1,3-glucanase, and a xylanase. The latter showed much weaker C_2,C_X, β-1,3-glucanase, and xylanase activites. The activities of the enzymes of the latter organism were one-twenty fifth to one-seventyth of those of the former.Optimum pH values for the activity of all the enzymes mentioned above (except C_2 activity, the optimum pH value of which was 4.0-4.5) were much the same, around pH 5.0.The two enzyme preparations seemed to be almost free from any proteolytic enzymes.From the result of a comparison of the macerating and polysaccharide decomposing activities these two preparations with those of some commercial preparations, it was supposed that some sort of endo-PG with higher affinity to an esterified substance than to a non-esterified one has something to do with maceration. However, it is possible that a complicated reaction of a pectolytic enzyme with C_2 activity or a xylanase activity has a part in maceration.

担子菌による植物組織の崩壊 : (第2報)粗酵素の各種多糖類分解活性について

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