Effect on the Synthesis of 1,3 propanediol of Organic acids in the Two-stage Fermentation / 中国生物工程杂志

Effect of organic acids on the synthesis of 1,3 propanediol was studied.The adsorption of organic acids from glycerol fermentation liquor by ion-exchange resins was investigated.The results showed that organic acid and 1,3 propanediol production was in negative relationship.The static adsorption showed that ion-exchange resin 005 had the best adsorption abilities of the organic acids in the glycerol fermentation liquor.It was showed that the yield of 1,3propanediol increased by 166% after the extraction of organic acids from glycerol fermentation liquor and the convertion rate increased by 34%.

Secretory Expression of the Fusion Protein PTH-HSA in Pichia pastoris / 中国生物工程杂志

The fused gene (PTH-HSA) of parathyroid hormone (PTH) gene and Human Serum Albumin(HSA) gene was amplified without linker by Overlapping PCR technology. The spliced gene was clone into Pichia pastoris secretory vector pPIC9K. With the help of promoter AOX1 and mat ? signal peptide, the PTH-HSA gene was designed to secretory expression.Linearized by restriction enzyme SalI, The recombinant plasmid pPIC9K/PTH-HSA was transformed into Pichia pastoris KM71 by electroporation. The recombinant strains which were identified by G418 and PCR analysis were induced by methanol to express protein PTH-HSA. The target protein was expressed in fermentation supernatant. Western blot analysis of the fusion protein showed that the expressed fusion protein PTH-HSA had the antigenicity of HSA.adenylate cyclase assay proved that the fused protein exhibited the bioactivity to stimulate cAMP synthesis The specific activity of broth was about 318IU/ml.

Construction Fermentation of Engineered Strain and Properties of Recombinant ?-glutamyltranspeptidase / 中国生物工程杂志

The ?glutamyltranspeptidase encoding gene(ggt) from Bacillus subtilis SYU 20016 was amplified by PCR. The ggt gene was inserted in pBV220 to yield the recombinant expression vector pBV220ggt. Overexpression of ggt in E.coli JM109 was achieved with pBV220ggt. SDSPAGE analysis showed an overexpressed recombinant product at about 65kDa,consistent with the molecular weight predicted from gene sequence. The ferment conditions of r-glutamyltranspeptidase were also discussed. The optimum temperature and pH for the enzyme were determined as 30℃ and 7.2 respectively.The cultures were incubated at 42℃ for 4h with broth volume 20ml/250ml flask and the yield of 6U/ml was obtained, enzyme activity of B. subtilis NX2 was only 3.2 U/ml.

Heterologous Expression of Zygosacharomyces rouxii ZrGpd 1 in Pichia farinosa / 中国生物工程杂志

To examine the effects of heterologous expression of ZrGPD1 (encoding glycerol 3-phosphate dehydrogenase ) cloned from osmotolerant yeast Zygosacharomyces rouxii on glycerol production in wild Pichia farinosa,the URA3 gene was amplified from P. farinosa as the homology integrative region. A recombinant plasmid (pUR-ZG) was constructed then transformed into P. farinosa by electroporation. The transformant pfa-gu was obtained by the selectable marker Zeocin TM . Primary results showed that the biomass of pfa-gu was higher than the wild type in the flask and after 72h fermentation the concentration of glycerol of pfa-gu was 37g/L enhanced 30% in comparison with the wild type. It is concluded that heterologous expression of ZrGPD1 is useful for increasing glycerol production and the ability of osmoregulation in P. farinosa.

SCREENING AND MUTATING A RAW STARCH-DIGESTING GLUCOAMYLASE STRAIN / 微生物学通报

strains that could produce raw starch-digesting glucoamylase were isolated from soil and mildewed rice.The highest raw starch-digesting glucoamylase activity strain named OR-1 was identified as Rhizopus.sp.The raw starch-digesting glucoamylase activity of the strain is 90U/mL.Through UV and NTG mutagenesis,the raw starch-digesting glucoamylase activity raised to 200U/mL and 325U/mL respectively.The RDA were 70% and 65% respectively.

SCREENING OF MONASCUS PRODUCING ONLY YE LLOW PIGMENTS / 微生物学通报

mutants which didnt produce red pigmen ts on malt extract agar plate were obtained.The 8 stable mutants were cultured on solid medium.Two samples wer e yellow,the others were white.The extracted samples were scanned in visible len gth.2 yellow samples showed only one absorptive peak at 370nm,the 6 white sample s showed no absorptive peak.The mutants producing only yellow pigments on solid medium were tested in liquid culture.The results indicated their ability to pro duce only yellow pigments were stable.