抄録
Continuous synthesis of oleic acid glycerides by seven Upases available commercially were compared at 40°C using the microporous hydrophobic membrane bioreactor we developed recently. The lipases produced by
Rhizopus japonicus,
Candida cylindracea, and
Phycomyces nitens were quickly inactivated in 97% glycerol solution and yielded very low glyceride conversions. The other four lipases yielded glyceride synthesis activities in the order:
Rhizopus delemer's<Pseudomonas fluorescens's< Mucor miehei's<Chromobacterium viscosum's. For these four lipases, there was a hyperbola-like relationship between the conversion and the amount of lipase adsorbed at the membrane during the reaction. The adsorbed lipase desorbed relatively easily when glycerol-water-lipase solution was replaced by fresh 97% glycerol solution having no lipases.
Mucor miehei's lipase was adsorbed more strongly than
Chromobacterium viscosum's. The product produced by
Mucor miehei's lipase was composed mostly of mono- and di-glycerides while the one produced by Pseudomonas fluorescens's was composed of mono-, di-, and tri-glycerides with an approximate molar ratio of 3:4:1. The contents of 2-monoglyceride and 1, 2-diglyceride isomers in the product having about 80% conversion produced by
Mucor miehei's lipase were quite small. The approximate half-life of
Mucor miehei's lipase was estimated as 54 days from a continuous reaction experiment carried out for 27 days.
