To examine the potential ability of edible mushrooms to act as biocatalysts, 19 basidiomycete strains were screened. Modified media (PG, O, and PGO medium) for liquid cultivation of these basidiomycete strains were de...To examine the potential ability of edible mushrooms to act as biocatalysts, 19 basidiomycete strains were screened. Modified media (PG, O, and PGO medium) for liquid cultivation of these basidiomycete strains were designed and tested. Wet cells (>10 g) of 4 basidiomycete strains (Pleurotus salmoneostramineus H7, P. salmoneostramineus H13, Ganoderma lucidum NBRC31863, Flammulina velutipes NBRC31862) were harvested from PGO medium for 7 days. The stereoselective reduction of α-keto esters using the 4 strains was tested. It was found that each of these strains had a reducing activity toward 6 aliphatic α-keto esters. In the presence of L-alanine as an additive, the reduction of ethyl 2-oxobutanoate and ethyl 2-oxopentanoete by P. salmoneostramineus H7 produced the corresponding alcohol with a high conversion ratio and with excellent enantiomeric excess (>99% e.e. (R)). Furthermore, ethyl pyruvate, ethyl 2-oxobutanoate, and ethyl 2-oxopentanoate were predominantly reduced to the corresponding (R)-hydroxy ester (>99% e.e.) by G. lucidum. Thus, we found that these edible mushrooms have great potential to be used as biocatalysts for the stereoselective reduction of carbonyl compounds.展开更多
To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified me...To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified media (1076-25% and P-1076-25% media) for liquid culture of these marine-derived actinomycetes were tested. As a result, 2 Micromonospora strains (Micromonospora sp. NBRC107096 and 107097) cultured with the 1076-25% medium and 2 Streptomyces strains (Streptomyces tateyamensis NBRC105048 and Streptomyces sp. NBRC105896) cultured with P-1076-25% medium showed a good growth. The stereoselective reduction of α-keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various α-keto esters. The introduction of L-glutamate or sucrose as an additive remarkably increased the conversion ratios in the reduction of substrates by the Micromonospora strain. Furthermore, in the presence of L-alanine, Streptomyces tateyamensis NBRC105048 reduced ethyl pyruvate, ethyl 2-oxobutanoate, ethyl 2-oxopentanoate, ethyl 2-oxohexanoate, and ethyl 3-methyl-2-oxobutyrate to the corresponding α-hydroxy ester with a high conversion ratio and with excellent enantiomeric excess. Thus, we found that these marine-derived actinomycetes have great potential to be used as biocatalysts for stereoselective reduction of carbonyl compounds.展开更多
Surface display is effectively utilized to construct a whole-cell biocatalyst.Codon optimization has been proven to be effective in maximizing production of heterologous proteins in yeast.Here,the cDNA sequence of Rhi...Surface display is effectively utilized to construct a whole-cell biocatalyst.Codon optimization has been proven to be effective in maximizing production of heterologous proteins in yeast.Here,the cDNA sequence of Rhizopus oryzae lipase (ROL) was optimized and synthesized according to the codon bias of Saccharomyces cerevisiae,and based on the Saccharomyces cerevisiae cell surface display system with α-agglutinin as an anchor,recombinant yeast displaying fully codon-optimized ROL with high activity was successfully constructed.Compared with the wild-type ROL-displaying yeast,the activity of the codon-optimized ROL yeast whole-cell biocatalyst (25 U/g dried cells) was 12.8-fold higher in a hydrolysis reaction using p-nitrophenyl palmitate (pNPP) as the substrate.To our knowledge,this was the first attempt to combine the techniques of yeast surface display and codon optimization for whole-cell biocatalyst construction.Consequently,the yeast whole-cell ROL biocatalyst was constructed with high activity.The optimum pH and temperature for the yeast whole-cell ROL biocatalyst were pH 7.0 and 40 °C.Furthermore,this whole-cell biocatalyst was applied to the hydrolysis of tributyrin and the resulted conversion of butyric acid reached 96.91% after 144 h.展开更多
This article summarizes the achievements of the authors' group in the area of biocatalyst catalyzed organic reactions in recent 10 years. A strain of Geotrichum sp. obtained by screening is capable of stereos...This article summarizes the achievements of the authors' group in the area of biocatalyst catalyzed organic reactions in recent 10 years. A strain of Geotrichum sp. obtained by screening is capable of stereoselectively reducing a number of carbonyl compounds. In many cases, the stereochemistry is complementary with that obtained by baker's yeast. Therefore, this micro organism provides a useful pathway to the preparation of alcohol compounds with specific configurations. On the other hand, a number of plant sources have been screened for oxynitrilases and the hydrocyanation reactions of various arylcarboxaldehydes have been investigated. A “micro aqueous reaction system' was invented, by which a series of novel optically active cyanohydrins were prepared. On this basis, a high through put continuous reaction system has been designed. This paper also describes examples of the syntheses of bio active compounds by using the optically active compounds obtained from the above mentioned catalytic reactions as precursors.展开更多
文摘To examine the potential ability of edible mushrooms to act as biocatalysts, 19 basidiomycete strains were screened. Modified media (PG, O, and PGO medium) for liquid cultivation of these basidiomycete strains were designed and tested. Wet cells (>10 g) of 4 basidiomycete strains (Pleurotus salmoneostramineus H7, P. salmoneostramineus H13, Ganoderma lucidum NBRC31863, Flammulina velutipes NBRC31862) were harvested from PGO medium for 7 days. The stereoselective reduction of α-keto esters using the 4 strains was tested. It was found that each of these strains had a reducing activity toward 6 aliphatic α-keto esters. In the presence of L-alanine as an additive, the reduction of ethyl 2-oxobutanoate and ethyl 2-oxopentanoete by P. salmoneostramineus H7 produced the corresponding alcohol with a high conversion ratio and with excellent enantiomeric excess (>99% e.e. (R)). Furthermore, ethyl pyruvate, ethyl 2-oxobutanoate, and ethyl 2-oxopentanoate were predominantly reduced to the corresponding (R)-hydroxy ester (>99% e.e.) by G. lucidum. Thus, we found that these edible mushrooms have great potential to be used as biocatalysts for the stereoselective reduction of carbonyl compounds.
文摘To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified media (1076-25% and P-1076-25% media) for liquid culture of these marine-derived actinomycetes were tested. As a result, 2 Micromonospora strains (Micromonospora sp. NBRC107096 and 107097) cultured with the 1076-25% medium and 2 Streptomyces strains (Streptomyces tateyamensis NBRC105048 and Streptomyces sp. NBRC105896) cultured with P-1076-25% medium showed a good growth. The stereoselective reduction of α-keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various α-keto esters. The introduction of L-glutamate or sucrose as an additive remarkably increased the conversion ratios in the reduction of substrates by the Micromonospora strain. Furthermore, in the presence of L-alanine, Streptomyces tateyamensis NBRC105048 reduced ethyl pyruvate, ethyl 2-oxobutanoate, ethyl 2-oxopentanoate, ethyl 2-oxohexanoate, and ethyl 3-methyl-2-oxobutyrate to the corresponding α-hydroxy ester with a high conversion ratio and with excellent enantiomeric excess. Thus, we found that these marine-derived actinomycetes have great potential to be used as biocatalysts for stereoselective reduction of carbonyl compounds.
基金Project supported by the National High-Tech R & D Program (863) of China (No. 2006AA10Z308)the National Science Foundation of China (No. 20776130)+1 种基金the Zhejiang Provincial Natural Science Foundation of China (No. Y4090309)the Zhejiang Provincial Science and Technology Program of China (No. 2009C32009)
文摘Surface display is effectively utilized to construct a whole-cell biocatalyst.Codon optimization has been proven to be effective in maximizing production of heterologous proteins in yeast.Here,the cDNA sequence of Rhizopus oryzae lipase (ROL) was optimized and synthesized according to the codon bias of Saccharomyces cerevisiae,and based on the Saccharomyces cerevisiae cell surface display system with α-agglutinin as an anchor,recombinant yeast displaying fully codon-optimized ROL with high activity was successfully constructed.Compared with the wild-type ROL-displaying yeast,the activity of the codon-optimized ROL yeast whole-cell biocatalyst (25 U/g dried cells) was 12.8-fold higher in a hydrolysis reaction using p-nitrophenyl palmitate (pNPP) as the substrate.To our knowledge,this was the first attempt to combine the techniques of yeast surface display and codon optimization for whole-cell biocatalyst construction.Consequently,the yeast whole-cell ROL biocatalyst was constructed with high activity.The optimum pH and temperature for the yeast whole-cell ROL biocatalyst were pH 7.0 and 40 °C.Furthermore,this whole-cell biocatalyst was applied to the hydrolysis of tributyrin and the resulted conversion of butyric acid reached 96.91% after 144 h.
基金theNationalNaturalScienceFoundationofChinaandStateMinistryofScienceandTechnology (No .G2 0 0 0 0 775 0 6)
文摘This article summarizes the achievements of the authors' group in the area of biocatalyst catalyzed organic reactions in recent 10 years. A strain of Geotrichum sp. obtained by screening is capable of stereoselectively reducing a number of carbonyl compounds. In many cases, the stereochemistry is complementary with that obtained by baker's yeast. Therefore, this micro organism provides a useful pathway to the preparation of alcohol compounds with specific configurations. On the other hand, a number of plant sources have been screened for oxynitrilases and the hydrocyanation reactions of various arylcarboxaldehydes have been investigated. A “micro aqueous reaction system' was invented, by which a series of novel optically active cyanohydrins were prepared. On this basis, a high through put continuous reaction system has been designed. This paper also describes examples of the syntheses of bio active compounds by using the optically active compounds obtained from the above mentioned catalytic reactions as precursors.
