Screening for Fungi That Have High Lipolytic and Acidolytic Activities in Biomass Support Particles

抄録

Extensive screening for cell-bound lipase-producing filamentous fungi suitable for immobilization in biomass support particles (BSPs) was done. A total of 91 fungi were assayed for their lipolytic activity after cultivation and immobilization in BSPs. In the cultivation, polypepton and oleic acid were used as an organic nitrogen source and a lipase inducer, respectively. Several species, such as Rhizopus species and Rhizomucor miehei, showed higher cell-bound lipolytic activity than that of Rhizopus chinensis, which is known to have considerable high cell-bound lipolytic activity from previous work. For two strains of fungi (Rhizopus stolonfer, Rhizomucor miehei), the cell-bound lipolytic activities of cells immobilized in BSPs did not show strong dependence on polypepton concentration (10-60 g/liter), while the extracellular lipolytic activities in the culture liquid increased with the increase in the polypepton concentration. Thirteen fungi that showed high cell-bound lipolytic activities were examined with respect to their acidolytic activities using fish oil and caprylic acid in n-hexane. There was a roughly proportional relationship between lipolytic and acidolytic activities (the linear correlation coeflicient, R, was 0.63). As the most potent fungus having the highest cell-bound acidolytic activity in BSP, Rhizomucor miehei IFO 9740 was selected.