Protease production during growth and autolysis of submerged Metarhizium anisopliae cultures

Abstract

The growth and autolysis of two strains of the entomopathogenic deuteromycete fungus Metarhizium anisopliae var. anisopliae were evaluated in medium containing casein or glucose as carbon source. Parameters such as economic coefficient and degree of autolysis were determined for each strain. Protease production was determined throughout the growth and autolysis phases of the cultures on medium under conditions of protease induction (in the presence of casein as sole source of carbon and nitrogen). The fungus was shown to utilize casein as a carbon/energy source in a more efficient manner than glucose. The autolysis shown by the strains was intense under both types of growth conditions, reaching up to 62.7% of the dry mass produced and started soon after the depletion of the exogenous carbon source. The relationship between the proteolytic activities of the two strains evaluated varied significantly (a maximum of 19.78 on the 5 th day and a minimum of 2.03 on the 16 th day of growth) during the various growth and autolysis phases, clearly showing that the difference between the growth curves and the difference in the kinetics of enzyme production may decisively affect the process of strain selection for protease production.

Atividade proteolítica de isolados de Metarhizium anisopliae sobre substratos cuticulares e não-cuticulares

“…Variabilidade genética na produção de proteases extracelulares foi verificada para isolados de M. anisopliae quando cultivados em meio completo contendo caseína como fonte de nitrogênio (ROSATO et al, 1981). Tal variabilidade também foi constatada em ensaios enzimáticos com diferentes isolados de M. anisopliae em meio líquido, contendo caseína como única fonte de nitrogênio (BRAGA et al, 1999;PINTO et al, 2002).…”

Cuticle-Degrading Proteases Produced by Metarhizium anisopliae and Their Induction in Different Media

“…Few isolates showed high proteolytic activity on 10th day. Caseinolytic and elastolytic activity of an M. anisopliae isolate was observed to be high during 4-6 days of culture and then a steep decrease up to 16th day of culture and this probably may be due to increasing degree of autolysis of the aging culture [16]. Among the M. anisopliae isolates studied, isolate UM6 showed highest enzyme activity on all the days of culture incubation.…”

Purification and characterization of the cuticle-degrading proteases produced by an isolate of Beauveria bassiana using the cuticle of the predatory bug, Andrallus spinidens Fabricius (Hemiptera: Pentatomidae)

“…This is because the integument of insects is the first barrier against the germ tube of the entomopathogenic fungi as it tries to reach the hemolymph (Gillespie et al 1998). Entomopathogenic fungi utilise two major proteases known as subtilisin-like serine protease (Pr1) and trypsin-like protease (Pr2) (St. Lager et al 1986;Braga et al 1999;Dias et al 2008) to overcome this barrier. Several entomopathogenic fungi, such as: Beauveria bassiana, Metarhizium anisopliae, Lecanicilium lecanii, Numuraea rileyi, and Metarhizum flavoviride have demonstrated Pr1 and Pr2 activities (Bidochka and Meltzer 2000).…”