The phytate and phytase of soybean tempeh

Soybeans were fermented into tempeh by Rhizopus oligosporus NRRL 2710. The phytic acid content of soybeans was reduced by about one-third as a result of this fermentation, while an equivalent amount of phosphate was released in the tempeh. The reduction of phytic acid was due to phytase elaborated by the mould of the fermentation. The pH optimum of this enzyme was 5.6 and the K_m of the phytase-phytate reaction was 0.28 × 10^?3 M.