Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol / 药物分析学报

Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulosc Congo red coltnre medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.

Characterization and biocompatibility of human-like collagen-hyaluronic acid scaffold for blood vessel / 生物工程学报

Human-like collagen (HLC) was cross-linked with hyaluronic acid by genipin in different ratio. The concentrations of hyaluronic acid in the mixture were 0, 0.01%, 0.05% and 0.1%. The blood vessel tubular grafts were then fabricated by freeze-drying. Microstructure, element composite, mechanical properties, cytotoxicity grade, and biocompatibility of different vascular scaffold groups were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), tensile test, burst pressure experiment, cytotoxicity experiment, endothelial cells planted in blood vessel scaffolds and hypodermic embedding of mice. The results showed that HLC-HA (0.05%) tubular scaffold exhibited interconnected well-distributed and porous structure and porosity of 94.38%; achieved the desirable mechanical property with stress of (1000.8 +/- 7.9) kPa and burst pressure of (1058.6 +/- 8.2) kPa, hypocytotoxicity, favourable cytocompatibility, hisocompatibility and disposition of degradation.

Anaerobic Biohydrogen Production Bacteria Selection and Its Optimization of Biohydrogen Fermentation Process / 微生物学通报

This research adopted silt as the sample,and the five highest hydrogen production performing strains contained in the sample were isolated. The strain whose hydrogen production was the highest was identified as Enterobacter cloacae by the analysis of 16S rDNA sequencing and comparison. It is showed by Plackett-Burman Experimental Design that only glucose,citric buffer and reducing agent had significant effects on hydrogen production by Enterobacter cloacae FML-C1. The path of steepest ascent was undertaken to approach the optimal response region of those three factors. Central Composite Design(CCD) and Response Surface Methodology(RSM) were employed to investigate the interaction of the variables and to ascertain the optimal values of the factors,which finally led to the maximum hydrogen production(VH2) . The theoretical optimal medium conditions were:glucose 21.5 g/L,citric buffer 13.6 mL/L,reducing agent10.0 mL/L. The five tentative tests matched this model well. The final VH2 was up to 2347.4 mL/L,which was 127.42% enhanced in comparison to the original. The result shows that PB experiment design and RSM analytical method work well in selecting factors which have significant influences on the hydrogen production and,moreover,achieve the ideal optimal result.

Optimization of Recombinant E. coli High-density Fermentation for Expressing Human-like CollagenⅡ / 微生物学通报

To study and optimize the fermentation parameters for expressing human-like collagenⅡduring E. coli high-density fermentation. The effects of pH, temperature, dissolved oxygen and induction instant on the cell growth and human-like collagenⅡproduction were investigated to optimize the fermentation conditions. The results demonstrated that the following conditions were beneficial for cell growth and foreign gene expression, controlling pH in phase induction at 6.8 and initial pH at 6.5, maintaining fermentation temperature and dissolved oxygen concentration was controlled at 34?C and 20% respectively, and implementing induction at the later logarithmic growth phase. Under the optimized condition, the cell density and human-like collagenⅡyield could reach 88.4 g/L and 14.2 g/L, respectively.