Application of Novel Preparation Method for Surfactant-Protease Complexes Catalytically Active in Organic Media

Abstract

We have applied the newly developed method of preparing surfactant-enzyme complexes to other different enzyme sources in order to study the efficacy of this technique in the catalyzed transesterification processes. Protease from varied material sources was modified with surfactant molecules utilizing water-in-oil (W/O) emulsions, and the complex so formed proved very effective in catalyzing vinyl butyrate transesterification with benzyl alcohol in organic media. By contrast, native commercial protease and a lyophilized protease from optimum buffer solution pH hardly catalyzed the above process. Although, conventionally prepared surfactant-coated protease had shown some catalytic activity, its performance was significantly lower than that of the surfactant-protease complex assembled in the novel preparation method. The typical transesterification rates catalytically induced by surfactantprotease complexes were in the range of 7-260-fold superior relative to other catalyzed reaction systems. The preparation and reaction conditions of the surfactant-protease P (Aspergillus melleus) have been optimized through studies of the effect of aqueous pH in the W/O emulsions, the nature of the organic solvents and surfactants, and the reaction temperature. The protease complex prepared from nonionic surfactant 2C 18 ∆ 9 -GE at optimized aqueous pH yielded the best results in isooctane at 45°C. This novel enzyme modification method is conceptually simple, and the resultant complexes are elucidable. It is hoped that this method will become useful, particularly in preparing enzymes that are nonaqueous media sensitive and soluble in organic solution.

Characterization and Catalytic Property of Surfactant‐Laccase Complex in Organic Media

“…Dordick and coworkers reported that adding a large amount of KCl at the preparation stage (20) activates the catalytic activity of subtilisin Carlsberg in organic media. The effect of salts has also been observed in a surfactant-protease complex in our previous study (13). The oxidized product in the reaction medium was analyzed by direct ionization mass spectrometry (DIMS) and was identified as 2,3-diaminophenazine (M + , 210), which is the same as the reaction product catalyzed by native laccase in an aqueous buffer solution (21) (data not shown).…”

“…For example, the surfactantlipase, surfactant-protease, and surfactant-peroxidase complexes that were prepared by this novel method exhibited much higher catalytic activities compared to their native powder enzymes in various anhydrous organic media (12)(13)(14). This novel preparation method can be easily applied to many enzymes.…”

Surfactant-histidine-heme ternary complex as a simple artificial heme enzyme in organic media

“…Our recent work was focused on the novel preparation method utilizing water-in-oil (W/O) emulsions for surfactant-enzyme complexes. It has been confirmed that the surfactant-enzyme complexation technique is feasible by employing lipase , ␣-chymotrypsin (Abe et al, 1997), various proteases (Okazaki et al, 1997b), and horseradish peroxidase as model enzymes. The resultant complexes were soluble and catalytically active in nonaqueous media.…”

Catalytic and Structural Properties of Surfactant‐Horseradish Peroxidase Complex in Organic Media

“…Our recent works were focused on surfactant-enzyme complexes, which are different from ordinary surfactantcoated enzymes (Okahata and Ijiro, 1988;Goto et al, 1994) owing to the different preparation techniques Okazaki et al, 1997a). The novel preparation method utilizing W/O emulsions for surfactant-enzyme complexes has been established, and its utility has been confirmed by employing a lipase (Okazaki et al, 1997a), R-chymotrypsin (Abe et al, 1997), and other proteases (Okazaki et al, 1997b). The resultant complexes are soluble and catalytically active in nonaqueous media.…”