Sunday, April 29, 2007

Protease production by different thermophilic fungi in solid state and submerged fermentation

Mariana M. Macchione, Carolina W. Merheb, Eleni Gomes, and Roberto Da Silva. Laboratorio de Bioquimica e Microbiologia Aplicada, IBILCE Instituto de Biociencias Letras e Ciencias Exatas, UNESP, Rua Cristovao Colombo, 2265, Sao Jose do Rio Preto, Brazil

Protease production by 7 thermophilic fungi Thermoascus aurantiacus Miehe, Thermomyces lanuginosus, Thermomyces lanuginosus TO.03, Aspergillus favus 1.2, Aspergillus favus 13.34, Rizomucor pusilus 13.36 and Rizomucor sp.13.37 was studied in different cultivation mediums containing proteins as enzyme inducers. Production was carried out in SSF and SmF. Best results of protease activity took place in SSF, using wheat bran as substrate. The fungi that stood out as best protease producers in SSF were T. lanuginosus, T. lanuginosus TO.03, Aspergillus favus 13.34, and Rizomucor sp 13.37, and in SmF were T. aurantiacus, T. lanuginosus TO.03 and Rizomucor sp. 13.37. Aspergillus favus 1.2 and Rizomucor pusilus 13.36 showed the lowest values of protease activity in both types of fermentation. Four different substrates were used to assay protease activity: HPA (Hide Powder Azure), casein, azocasein and azoalbumin. Azoalbumin exhibited the best results. Protease from T. aurantiacus was chosen for cysteine protease evaluation and was assayed in the presence of reducing agents DTT (dithiothreitol) and b-mercaptoethanol. Results did not shown evidence that it was a cysteine protease.


Financial support: FAPESP