Rhizopus microsporus var. rhizopodiformis: a thermotolerant fungus with potential for production of thermostable amylases.
The effect of several nutritional and environmental parameters on growth and amylase production from Rhizopus microsporus var. rhizopodiformis was analysed. This fungus was isolated from soil of the Brazilian "cerrado" and produced high levels of amylolytic activity at 45 degrees C in liquid medium supplemented with starch, sugar cane bagasse, oat meal or cassava flour. Glucose in the culture medium drastically repressed the amylolytic activity. The products of hydrolysis were analysed by thin layer chromatography, and glucose was detected as the main component. The amylolytic activity hydrolysed several substrates, such as amylopectin, amylase, glycogen, pullulan, starch, and maltose. Glucose was always the main end product detected by high-pressure liquid chromatography analysis. These results indicated that the amylolytic activity studied is a glucoamylase, but there were also low levels of alpha-amylase. As compared to other fungi, R. microsporus var. rhizopodiformis can be considered an efficient producer of thermostable amylases, using raw residues of low cost as substrates. This information is of technological value, considering the importance of amylases for industrial hydrolysis.
Peixoto
Simone C
SC
Departamento de Biologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Ribeirão Preto SP, Brazil.
Jorge
João A
JA
Terenzi
Héctor F
HF
Polizeli
Maria de Lourdes T M
Mde L
D000064:Acclimatization; D000681:Amylases / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D004795:Enzyme Stability; D006358:Hot Temperature; D007700:Kinetics; D009584:Nitrogen / Q000378:metabolism; D012233:Rhizopus / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D013379:Substrate Specificity; D013816:Thermodynamics; D000516:alpha-Amylases / Q000302:isolation & purification / Q000378:metabolism
D002244:Carbon; D000681:Amylases; D000516:alpha-Amylases; D009584:Nitrogen