Abstract:

Abstract:The recombinant plasmid pPIC-gpd-bgl-hyg was constructed, which contained GPD2 promotor and terminator from industrial yeasts Saccharomyces cerevisiae, b-glucosidase gene (BGL1) from Saccharomycopsis fibuligera and hyg from hygromycin as the selected marker. With the yeast’s high efficiency of homologous integrated, the BGL1 gene was successfully integrated into industrial yeasts S. cerevisiae. The recombined yeast could grow on the cultures with the cellobiose as a sole carbon source, and the β-glucosidase activity achieved 0.764 U/mL after 48 hours’ cultivation. In the experiments of VHG ethanol fermentation, the cellobiose concentration in broth of recombined yeast was 80% lower than that of industrial yeast.

Abstract:Hydrogenases are key enzyme for bio-hydrogen production, most of them were rapidly inactivated by oxygen. It is important to bio-hydrogen production and hydrogen application that improve the O2-tolerance of hydrogenase. In this experiment, the hydrogen producing strain Klebsiella oxytoca HP1 was treated with 1% ethyl methanesulfonate(EMS) , the mutants with high O2-toleration ability were screened with 40mmol/L metronidazole (MNZ) and 21% oxygen. The H2-evolving activity of the first generation mutant HP1-A15 was increased 3.70 times than that of the wild-type (WT) under 15% oxygen. The H2-evolving activity of the second generation mutant HPA15-37 was enhanced 11 times than that of WT under the condition of 21% oxygen. The mutants HP1-A15 and HPA15-37 had steady heredity. These results suggest that MNZ and in addition oxygen is a good way to screen of O2-tolerate phenotype of facultativeanaerobe with high H2-evolving activity.

Abstract:A batch laboratory test was conducted to examine the effect of biological reductive dechlorination of 2,4-Dichlorophenol(2,4-DCP) by the addition of zero-valent iron(Fe0) in the anaerobic system, through inoculating the anaerobic mixed microorganism acclimated for two months. Meanwhile, several factors that affected “Fe0+ microbe” system were also being discussed. The results showed that, “Fe0+ microbe” system accelerated the biological dechlorination of 2,4-DCP effectively compared to the individual use. The optimum quantity of added Fe0 and inoculation was 0.5 g/L and 376.2 mgVSS/L in the combined system respectively. It showed the most effective transformation efficiency for 2,4-DCP when initial pH=8.0, whereas it become weaker when initial pH are keeping in acid condition. There existed a proportion between quantity of added Fe0 and inoculation. It enhanced degradable effect of 2,4-dichlorophenol when increased the quantity of inoculation at suitable ranges, which generated more enzyme or enzymatic series degraded pollutant.

Abstract:More than 20 strains capable of producing dihydroxyacetone from glycerol were isolated from 4 different natural environment samples by using two detection methods. The strain 6-8 which could grow on medium containing glycerol as sole carbon source had a higher converting capability. Under a better culture, the highest DHA production of the strain 6-8 reached 6.4 g/L. In addition to general morphological and biochemical characteristics, the strain 6-8 was identified by 16S rDNA sequence and systematic analysis. The results showed that 16S rDNA sequence of the strain 6-8 had similarity of 99.7% with Acinetobacter sp. suggesting that the strain 6-8 is one of subspecies of Acinetobacter sp.

Abstract:The key factors on high-level polygalacturonate lyase (PGL) production in recombinant Pichia pastoris were investigated. In 250 mL shake flask, the optimal glycerol concentration, initial methanol concentration, methanol supplementation quantity, duration of induction, initial pH, medium volume were 40 g/L, 3.1 g Methanol/g DCW, 0.51 g Methanol/g DCW (in every 24 h), 72 h, pH6.0 and 30 mL, respectively. In 7 L fermentor, constant glycerol feeding, constant and DO-stat methanol feeding strategies were applied to enhance cell density and PGL production. Finally, the dry cell weight was 80 g/L, and the maximum yield of PGL was achieved to 217 U/mL, increased by 66.2% than that of flask level.

Abstract:Two pathogenic strains zouA and zouB were isolated from Litopenaeus vannamei larvae which suffered from vibriosis, and were identified as Vibrio alginolyticus and V. parahaemolyticus by traditional bacterial identification method respectively. Strain zouB was confirmed further as V. parahaemolyticus by special R72H sequence test. 16S rRNA and heat shock protein (HSP60) genes partial sequences of strain zouA were determined. Phylogenetic tree of vibrios based on 16S rRNA gene sequences revealed that there was more than 98% sequence identity among zouA, V. alginolyticus, V. parahaemolyticus, et al., and could not be distinguished between each other. HSP60 gene sequences showed that strain zouA had sequence identity of more than 98% to V. alginolyticus, whereas had less than 92% to that of all the other vibrios. Combining phenotypic and molecular characters, zouA and zouB were identified as V. alginolyticus and V. parahaemolyticus respectively.

Abstract:The effect of C/N ratio and light intensity on the astaxanthin accumulation of Chlorella zofingiensis was studied in this research. C/N ratio showed obvious effect on the astaxanthin accumulation. Astaxanthin content rapidly increased with the enhancement of C/N ratio, while the alga growth was inhibited, the biomass was far lower than the control. The maximum astaxanthin yield of 9.19 mg/L was obtained at a C/N ra tio of 133. High light could farther enhance astaxanthin content and yield. A light intensity of 200 mmol/m2﹒scould induce maximum astaxanthin yield to 12.52 mg/L without serious inhibition in the biomass. Besides, the mechanisms of different induction were discussed, and the method combined heterotrophic and phototrophic culture was proposed to enhance astaxanthin production by C. zofingiensis.

Abstract:Chloro- and nitro- substituted aromatics are toxic and persistent in the environment. Pseudomonas putida ZWL73, isolated from 4-chloronitrobenzene (4CNB) polluted soil, can grow on 4CNB as carbon and nitrogen sources. Enzymatic analyses were carried out in order to illuminate the degradation pathway. Two key enzymatic acivities were found to be invovled in the degradation: the nitroreductase activity that catalyzing the first step and the ring-cleavage dioxygenase activity leading the substrate to be mineralized. The degradation was therefore decided to process through a partial reductive pathway together with the proofs of the results of degradation intermediates test and growth substrate test.

Abstract:A strain XT11 was isolated from environment, which could degrade polyvinyl alcohol. It belongs to the genus of Pseudomonas sp. The course curve of growth and PVA degradation were discussed. The results showed that 1 g/L of PVA could be completely degraded after 54 h cultivation. The initial pH of fermentation medium, culture temperature and the concentration of yeast extract were also discussed. The results showed that the optimum initial pH, culture temperature and the concentration of yeast extract were 7.0, 30℃ and 0.5 g/L respectively. Effect of the concentration of PVA on PVA degradation was discussed. The results showed that PVA degradation decreased as the concentration of PVA increased.

Abstract:In this paper, the effect of 5% (V/V) n-alkanes (e.g, n-Heptane, n-Octane, n-Decane, n-Dodecane, n-Tetradecane and n-Hexadecane) on the growth and protease production of organic-solvent-tolerant- bacterium Bacillus licheniformis YP1 was studied. 5%(V/V) n-alkanes had no effect on the stability of YP1 protease. 5% (V/V) n-alkanes had no notable influence on the yield of strain YP1 but dramatically affected the protease production. The presence of n-Heptane, n-Octane and n-Decane deeply repressed the protease production; however n-Dodecane, n-Tetradecane and n-Hexadecane enhanced the protease production prominencely. The concentration of n-Tetradecane (1%-8%, V/V) had a direct ration with the protease production. The detailed experiments showed that the notable increase of protease activity appeared at the late logarithm of cultivation compared with the blank. The cell shape of YP1 strain remarkably decreased when grown in the presence of n-Tetradecane. This is the first report about the effect of n-alkanes on the protease production by the solvent tolerant bacterium.

Abstract:The crenarchaeal diversity and phylogenesis of two hot springs in Tengchong were investigated and analyzed using the construction of 16S rRNA gene clone libraries. Total 18 crenarchaeal sequences were obtained and divided into 12 OTUs. The average similarities between the clone sequences from Wuming hot spring and Rebao hot spring and their closest sequences deposited in GenBank is 92.56% and 93%, respectively. Based on the phylogenetic tree constructed by using crenarchaeal 16S rRNA gene sequences, Wuming hot spring not only have hyperthethermophilic crenarchaeal clusters but also have the crenarchaeal clusters that have close phylogenetic relationship with non-thermophilic crenarchaeota. And most of the crenarchaeota in Rebao spring distribute in normal temperature groups. This study showed that crenarchaeal clusters in Tengchong hot springs have some differences with other hot springs in the world, and these springs represent two important environments for investigating the evolutionary origin of the non-thermophilic Crenarchaeoone library.

Abstract:A rare strain of actinomycetes, with broad-spectrum antimicrobial activity, was isolated from the soil samples from the farmland in the area of Yaohu lake in Nanchang. The information about the taxonomic identification, such as the morphology, physiological properties, cell components and 16S rRNA gene sequences, suggested that the rare strain of actinomycetes was identified as Micromonospora carbonacea.

Abstract:Streptomycin-resistant mutants were obtained from original strains YH04 treated by UV (253 nm, 30 W, 45 s or 60 s) under the selection pressure of resistance to streptomycin (the lethal concentration is 1.2 mg/mL). Streptomyces Strain YH9407 with high antibiotic yield and genetic stability was obtained from streptomycin-resistant mutants. The yield of antibiotic TS99 is more than 60% higher than that of the original strain.

Abstract:Two kinds of Rep-PCR, Repetitive extragenic palindromic elements-PCR(REP-PCR) and enterobacterial repetitive intergenic consensus sequences-PCR (ERIC-PCR), were used firstly in typing and genetic relationship research for Vibrio parahaemolyticus in China, and Hunter＆Gaston’s method was used to calculate discriminative index of REP-PCR and ERIC-PCR. Forty Vibrio parahaemolyticus strains, representing a wide range of REP and ERIC patterns, were grouped into 21 and 4 patterns with discriminative index of 0.953 and 0.5, by REP-PCR and ERIC-PCR respectively. G1 type was predominant in 40 strains of Vibrio parahaemolyticus when typed by REP-PCR. The results show that Rep-PCR is feasible for typing Vibrio parahaemolyticus strains, and REP-PCR possesses better typing potential. Similar DNA fingerprints were gained from serotype O1 and O3 strains by two kinds of Rep-PCR. This result indicate that the genetype of serovar O3 and O1 are closely related.

Abstract:In this paper, metabolic networks of the Corynebacterium glutamicum GWY020 and the two derivatives carrying additional mutations HUI821and GUI089 were established and modified. The concentrations of extra-cellular metabolites were determined under sub-steady-state (50 h~52 h) of the batch culture. The metabolic flux distribution maps of the three strains were obtained, compared and analyzed. These results indicate that the introduction of analog supersensitive marker or analog resistant marker skew the metabolic flux towards the formation of L-Arginine. This study revealed the usefulness of the metabolic flux analysis as a tool for verification of existing production strains. The analysis may play an important role in helping us to rationally re-design metabolism for further improvement of fermentation process.

Abstract:To investigate the rate of carriage, the phenotype, the genotype and homology in stool specimen from outpatients, inpatients and health adult for prevention and guiding the clinical treatment. According to CLSI’s guideline, antimicrobial susceptibility tests were performed; To detect vancomycin resistant gene by PCR; To analyze the homology by REP-PCR method. The vancomycin resistant carriage rate in intestinal tract of inpatients was 20.67%. All 22 isolates harbored VanA genotype; 9 isolates harbored VanC1 genotype. The homology in 22 vancomycin resistant enterococci was mostly type A, which was divided into A1-A5 subtypes, and they had high homology. Type A had 19 isolates. Of all, type A1 had 4 isolates; type A2 had 6 isolates; type A3 had 4 isolates; type A4 had 3 isolates; type A5 had 2 isolates. Type B、C、D had no subtypes. Three pairs of isolates had 100% homologies. There were 4 isolates (4%) separated from outpatients. All were vanC1 types. Two were likely to be the same isolate. There were 11 isolates (27.5%) separated from health adults. Of all, 8 isolates were VanC1, and the others were vanC2. The homology in 11 VIE was mostly type A, which was divided into A1-A4 subtypes. Type A1 had 1 isolate; type A2 had 2 isolates; type A3 had 1 isolate; type A4 had 1 isolate. Type D1、D2、D3 was 1 isolate separately. Type B、C、E had no subtypes. Two VIE from inpatients and two from outpatients had 100% homologies. The other two VIE from inpatients and two from outpatients had 100 homologies, too. They had low homology with the isolates from health adults.Minimum inhibitory concentration (MIC) of 22 VRE to vancomycin were > 512μg/mL; MIC of 16 VIE to vancomycin were 16μg/mL; MIC of 8 VIE to vancomycin were 8μg/mL. It is a risk factor for hospital infection that VRE carriage of inpatients in intestinal tract is high. There is 100% agreement between phenotypes and genotypes in 46 vancomycin resistance enterococci. VRE are multiresistant. Part isolates have high homology.

Abstract:Porcine Reproductive and Respiratory Syndrome virus (PRRSV) is the etiological agent of Porcine Reproductive and Respiratory Syndrome. We summarized the recent research progress on molecular biology of PRRSV including the structure of genome, viral structural and Non-structural protein.

Abstract:Polycyclic aromatic hydrocarbons (PAHs), which consist of two or more fused aromatic rings, are ubiquitous pollutants in the environment, and are of concern because of their toxic and carcinogenic potential. In nature, the aerobic bacterial bio-treatment of contamination with PAHs is of the major route. It is obvious that the degraders are more useful for the bioremediation of contaminated environments and may be potentially used in a wide of application. Therefore, many researchers have been focusing on the biodegradations of PAHs by various aerobic bacteria. In the last two decades, the mechanism of degradation in bacteria capable of aero-biotic utilizing PAHs has been well investigated in genetic studies such as diversities of genes of PAHs metabolism, the genes which participate directly in PAHs metabolism and the genetics mechanism of bacterial population and so on. In brief, most of PAH-catabolic genes are classed into two groups according to their identity. One group is called “the nah-like genes”, the other group, i.e. “the nah-unlike genes” is different from the nah-like genes. The different molecular genetics mechanisms of bacterial population adapted to PAH compound will be dealt with in three groups: (i) point mutations, (ii) gene transfer, and (iii) DNA rearrangements and absentation. In this review, some genetic knowledge about aerobic bacteria with the mechanism for the degradation of PAHs is summarized.

Abstract:At present, microbe surface display system mainly involves phage surface display system, bacterial surface display system, yeast surface display system and virus surface display system. Baculovirus surface display system is a new type of eukaryote surface display system which developed based on deeply understanding of construction and function of virus genome in recent years. Through fused expression with viral capsid or membrane proteins exogenous peptides can be displayed on the surface of the virus and formed hedgehog-shape “fake virus”. Baculovirus surface display system was characterized by safeness and high performance, furthermore, this system can complete post-translation processing and modification of protein to enhance the bioactivity of exogenous product. Combined with the author’s experimental work, this paper briefly introduces the mechanism and traits of this system and summarizes the newest research development on its application in the field of monoclonal antibody preparation, new-type vaccine development, genes transduction and genes therapy. It is believed that the system above may show extensive application through further improvement and optimization.

Abstract:Microbiological test of the plant extracts is an important measure to guarantee the safety of the plant extracts products. It is important to establish strict criterion system of the plant extracts quality control, especially for functional food, food additive and daily use chemicals from the plants. We elaborate on great significance of microbiological test of the plants extracts to the quality and safety of the plant extracts products, which is critical problem for the integrated development of the plant extracts industry. In this paper we introduced the current research and development trends on microbiological detection techniques, and also give some advice on how to establish a new standard system of microbiological test of the plant extracts industry, so that our plant extracts industry has competitive advantages on the international markets.

Abstract:The growth curve of single cell organisms in batch cultivation could divide into 6 phases, lag phase, acceleration phase, log phase, deceleration phase, stationary phase, and death phase, based on specific growth rate during cultivation process. There were significantly differences between deceleration phase and the other phases in cell growth, substrate consumption, product formation, and genes express profile. The deceleration phase was highly important to fermentation process. However, cognizing and teaching to the deceleration phase had been considerably weakened since a long period. So it should be strengthened.

Abstract:This paper reviews the recent advances in recombinant expression and purification of defensins, including the choice of host cells, vectors and expression strategies in prokaryotic and eukaryotic cell expression systems, as well as the status of purification processes. By summarizing the problems existed in the production and clinical applications of defensins, the authors here also pointed out the research directions for defensins, and conceived the prospects for its exploitation in the future.

Abstract:The complex of insect mycoses by entomopathogenic fungi includes, in general, spore adhering, cuticle penetration, hemocoel colonization and host death. Recent gene function studies of Metarhizium anisopliae and Beauveria bassiana have bettered the understanding of the mechanisms of molecular entomopathogenicity that there are different genes involved in different infection stages. With the identifications of different virulent genes and the exploring of exogenous toxins, genetic engineering works have been reviewed in this paper to demonstrate the potentials to improve the control efficacies of mycoinsecticides by the strategy of toxin gene overexpression. Future studies are discussed to further explore fungal virulent genes and their functions during infection processes.

Abstract:Teaching method for basal experiment, comprehensive experiment, design experiment and teaching practice in food microiological analysis were elaborated completely, and design experimental teaching was discussed stress. At the same time, Through introducing various experience of the design experiment teaching, resolvent and way of thinking against problem meeted in design experiment teaching were put forward.

Abstract:As an important link of practice teaching, the Fermentation Engineering and Equipment Course Design can play the connecting role between the preceding and the following in the practice teaching, and lay a good foundation for the students to work in the factory after graduation. The article shall exchange and discuss the teaching links, such as the status, opinion, contents and way of the course design.

Abstract:Terminal restriction fragment length polymorphism (T_RFLP) analysis is a culture- independent approach for analyzing microbial community in environment. It bases on PCR technology, and its process includes DNA extraction of environmental samples, amplification of genes encoding the 16S rRNA, 18S rRNA or enzymes with fluorescently labeled primers, the restriction enzyme digestion of PCR products, capillary electrophoresis and the analysis of T_RFLP profile. It has been proved to be powerful applied on microbial community in environment since developed in 1997. Currently, T_RFLP rarely applied in China, and it has no applications on microbial community analysis of nitrifying bacteria. In this article, the fundamental principle of this technique and the recent applications of T_RFLP on microbial community are summarized; in addition, it illustrates the confinements of conventional culture-dependent of nitrifying bacteria and the foreground of T_RFLP applying on microbial community structure analysis of nitrifying bacteria.

Abstract:The samples of Spirulina (Arthrospira) platensis from different habitats were analyzed by the RAPD. The result shows that there are obvious differences in the molecular level between the Spirulina (Arthrospira) platensis from alkaline lakes in Erdos Plateau and the one from Chad Lake, and the homology of DNA in the amplified polymorphism of the Spirulina (Arthrospira) platensis only reaches 48.23%. The different habitats and geographical isolation are the primary reasons for the above-mentioned result.

Abstract:Genomic DNA of two fungi Thamnidium elegans and Umbelopsis isabellina were extracted with an amended Cetyltrimethyl Ammonium Bromide (CTAB) method. This modified method uses repeated freezing in liquid nitrogen and thawing with combination of shocking with glass beads to replace of the traditional method. Quality and concentration of DNA extracted by the modified methodwere tested. Compared with the traditional method, higher yield and purity of genomic DNA were obtained with less amount ofmycelium. The result indicted that this is a simple and highly efficient method, which is suitable to treat many samples at one time and for basic molecular experiments, such as restriction endonuclease reaction and PCR.

Abstract:A rapid multiplex PCR (m-PCR) method that allows the simultaneous detection,in a single tube, of two commonly encountered food-borne pathogens in meat and other animal products was developed. The invasion protein gene (invA) of Salmonella spp. and rfbE gene of Escherichia coli O157 were used as the gene targets. The multiplex PCR assay was specific and rapid,with a turnround time of 9 h~10 h.While the detection limit is 2.4×102 cfu/mL of Salmonella spp. and 2.2×102 cfu/mL of E.coli O157 respectively when detecting the artificially contaminated pork meat with incubation at 37℃ for 4 h. The m-PCR assay developed in this study could provide a cost-effective and informative supplement to conventional microbiological methods for routine monitoring of food.