Takó M, Farkas Elvira, Lung Szabina, Krisch Judit, Vágvölgyi C, Papp T
Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
Acta Biol Hung. 2010 Mar;61(1):101-10. doi: 10.1556/ABiol.61.2010.1.10.
Extracellular beta-glucosidase activity of 94 strains, representing 24 species of the genera Gilbertella, Mucor, Rhizomucor , and Rhizopus was evaluated in submerged culture and under solid state fermentation on wheat bran. Gilbertella persicaria G1 isolate showed the highest activity (70.9 U ml -1 ) followed by other Gilbertella (58.6-59.0 U ml -1 ) and Rhizomucor miehei isolates (29.2-42.0 U ml -1 ). Optimum temperature for enzyme production was 25 degrees C for Gilbertella and Mucor , and 30 degrees C for Rhizomucor and Rhizopus strains. Enzymes of R. miehei strains proved to be thermotolerant preserving up to 92.8% residual activity after heating to 75 degrees C in the presence of cellobiose substrate. Enzymes of Mucor racemosus f. chibinensis, R. miehei and Rhizopus microsporus var. oligosporus strains were activated at acidic condition (pH 4). Glucose was a strong inhibitor for each fungal beta-glucosidase tested but some of them showed ethanol tolerance up to 20% (v/v). Ethanol also activated the enzyme in these strains suggesting glycosyl transferase activity.
对代表吉尔伯托霉属、毛霉属、根毛霉属和根霉属24个物种的94个菌株在液体培养和麸皮固态发酵条件下的胞外β-葡萄糖苷酶活性进行了评估。波斯吉尔伯托霉G1分离株显示出最高活性（70.9 U ml-1），其次是其他吉尔伯托霉菌株（58.6 - 59.0 U ml-1）和米黑根毛霉菌株（29.2 - 42.0 U ml-1）。吉尔伯托霉属和毛霉属菌株产酶的最适温度为25℃，根毛霉属和根霉属菌株为30℃。米黑根毛霉属菌株的酶被证明具有耐热性，在存在纤维二糖底物的情况下加热至75℃后仍保留高达92.8%的残余活性。总状毛霉中华变种、米黑根毛霉和少孢根霉变种菌株的酶在酸性条件（pH 4）下被激活。葡萄糖对所测试的每种真菌β-葡萄糖苷酶都是一种强抑制剂，但其中一些显示出高达20%（v/v）的乙醇耐受性。乙醇也激活了这些菌株中的酶，表明存在糖基转移酶活性。
