Expression of proteases by Rhizopus species during Tempeh fermentation of soybeans

Abstract

Expression of proteolytic activities by nine Rhizopus strains during soybean fermentation to produce Tempeh has been determined. All strains showed activity at acidic, neutral, and alkaline pH values. In protein solubilizates prepared from Tempeh pronounced differences in the time course and intensity of maximum protease activities were observed between the isolates when measured at pH 7, the approximate pH of Tempeh during ripening. Proteases expressed by fungi during growth on Tempeh were solubilized and the enzymes were enriched by acetone precipitation and chromatographies with Phenylsuperose, Mono S, and Mono P, respectively. They were identified as one aspartic‐ (∼35 kD) and one serine (∼33 kD) protease, each existing in different isoforms. Proteases isolated from Tempeh were identical to those expressed during fungal growth in a soyprotein‐raffinosephytate liquid medium. The temperature stability of the Tempeh‐ and the cell wall‐isolated proteases is very low in contrast to the proteases secreted into the medium. Proteases isolated from Tempeh, cell walls and liquid media exhibit differences in the number of alkaline isoforms.

Biosynthesis of proteases by Rhizopus oligosporus IHS13 in low‐cost medium by solid‐state fermentation

“…The strain of Rhizopus oligosporus IHS 13 produced a substantial amount of proteases (7.0 U ml -1 ) on a very cheap substrate (soybean meal and wheat bran) under solid-state Effect of depth of substrate on the production of proteases by Rhizopus oligosporus IHS 13 fermentation conditions. The results of the present studies are very encouraging and superior to the previous reports (HAQ et al 2003, HESKAMP andBARZ 1998) and will have a great impact on the development of an inexpensive fermentation process for the production of proteases on laboratory and industrial scale.…”

Metagenomic analysis of microbial community in over-fermented tempeh

“…This group of fungi can grow predominantly on the substrate with an abundant amount of carbon (Ferreira et al 2012). Group of fungi from order Mucorales (Rhizopus sp., Rhizopus oligosporus, and Rhizopus oryzae) have a high hydrolytic activity such as amylolytic and proteolytic activity (Bauman and Bisping 1995; Heskamp and Barz 1998;Murashima et al 2002;Handoyo and Morita 2006). Fungi of the order Mucorales was suggested to have a role in the degradation of complex organic compounds such as fats, proteins, and carbohydrates contained in tempeh into simple organic compounds such as fatty acids, amino acids, peptides, and monosaccharides.…”

Tempe fermentation, innovation and functionality: update into the third millenium

“…Proteases of nine strains of R. oryzae , R. microsporus var. chinensis , Rhizopus stolonifer and R. oligosporus comprised various isoforms of aspartic ( ca 35 kD) and serine ( ca 33 kD) proteases (Heskamp and Barz 1998).…”