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Abstract:The antioxidant activities of fermented mycelial extracts with different concentrations of ethanol of Lepista sordida were individually determined in four test systems. The results showed that all the mycelial extracts had obvious effects on scavenging 1,1-diphenyl-2-picrylhydrazyl radical (·DPPH) and hydroxyl radical; and with the concentration of ethanol increasing, the antioxidant activities declined: the extract with deionized water at the concentration of 3 g/L mycelium, DPPH radical scavenging activity and hydroxyl radical scavenging activities were 90.55% and 81.90% respectively. At a concentration of 6 g/L mycelium in 50% and 70% ethanol extracts, the DPPH radical scavenging activities were 53.7% and 45.2%, and the hydroxyl radical scavenging activities were 79.4% and 78.4%. The extracts could also significantly inhibited the peroxidation of linoleic acid, within 64 hours at the concentration of 5 g/L, the inhibition ratios of the extracts with water, 50% and 70% ethanol were 100%, 96.0% and 89.2% respectively. The extracts possessed slightly restraining effects on pyrogallol autooxidation.

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Abstract:In this study, we report a novel system of gene knocking-out in C. utilis SZU 07-01 by successfully disrupting the gene of gsh1. First of all, the gsh1 (encoding γ-GCS protein) gene was cloned by genome walking method from C. utilis SZU 07-01 according to γ-GCS protein conservative sequences among several different yeasts. Then, the disrupting vector, pPICZalpha A-kan 3 was constructed on the basis of plasmid pPICZalpha A, whose original TEF promoter responding for kananmycin resistance gene (kan) transcription was replaced by GAP promoter (pGAP) isolated from C. utilis SZU 07-01. pPICZalpha A-kan 3 was linearized and then transformed into C. utilis, resulting in a gsh1 deleted heterozygotic mutant strain designated as GSH-6. After cultured in the same condition, the mutant deficient in glutathione biosynthesis showed decreases of 17.5%, 61%, 18.5% in γ-GCS activity, glutathione content and dry cell weight, respectively. The disruption element (pGAP: kan) used in this study supplies a new gene genetic manipulation approach to research the physiological function of GSH in C. utilis at a molecular level.

Abstract:A bacterial strain named as 2-1 was isolated from activated sludge, which can product 1,3-propanediol (1,3-PD) from glycerol. Morphologic properties, physiological and biochemical characteristics and 16S rRNA gene sequence analyses were used to identify the strain. The phylogenetic analysis of the 16S rRNA sequence indicated that the strain 2-1 closely with Klebsiella pneumoniae (CP001891), whereas, the homologous rate was 95.4%. The strain 2-1 might represent a new species. In the fed-batch fermentation at 5 L fermentor: the maximum concentration of 1,3-PD was 63.5 g/L; productivity was 2.19 g/(L·h); substrate conversion rate was 0.64 mol/mol.

Abstract:A novel fungus, named Tolypocladium cylindrosporum syzx4, which can efficiently produce extracellular β-glucosidase, was isolated from naturally rotten corn stover. It is first time to report the β-glucosidase produced by T. cylindrosporum gams using agro-industrial residues in SmF. The fermentation variables optimized by single-factor experiment approach were further optimized by statistical optimization. Results of Plackett-Burman design indicated the evaluation of the medium components could be ranked as: TCS>KH2PO4>SM=(NH4)2SO4. With the optimum medium, viz. TCS 25.72 g/L, SM 6.82 g/L, KH2PO4 1.90 g/L and (NH4)2SO4 3.21 g/L predicted by RSM model with others as the original, 2.21 U/mL β-glucosidase activity was obtained. The results suggest that the β-glucosidase can be used for various biotechnological applications.

Abstract:Bacterial strains with pectinase activity were isolated from Zimbabwe tobacco strips using pectin as carbon source. ARDRA patterns of 16S rDNA combined with 16S rDNA sequence analysis, physiological and biochemical experiments were used to identify the isolated strains. Different conditions including incubating time, growth temperature, initial pH and inoculation quantity for the enzyme production were also studied. The results indicated that bacteria isolated from Zimbabwe tobacco strips with high pectin-degrading ability mainly belong to Bacillus subtilis (genus Bacillus) and Alcaligenes faecalis (genus Alcaligenes). Among these strains, Bacillus subtilis strain T10 possessed the highest pectinase activity (571 U/mg) and polygalacturonate lyase activity (297 U/mg) under its optimum enzyme fermantation conditions, which use 6% (V/V) culture fluid as the inoculum for enzyme production in the initial pH 7.5 fermentation medium at 35 °C for 48?56 h.

Abstract:A strain CCZU-12 with high glycolonitrile-hydrolyzing activity has been isolated using glycolonitrile as sole nitrogen source. It was identified as Pseudomonas sp. by its morphological, physiological properties and 16S rDNA sequence analysis. The preferred carbon/nitrogen sources and metal ions were sodium acetate (10 g/L), yeast extract (5 g/L), and Mg2+ (1.0 mmol/L), respectively. The optimum culture conditions were the filling volume 50 mL in 250 mL shaking flask, inoculum 4%, temperature 30 °C, and initial pH 7.0. After hydrolysis of glycolonitrile for 120 h, glycolic acid was obtained in a yield of 98.9% at the optimum reaction temperature 35 °C and pH 7.0.

Abstract:The pH and ionic conductivity change of the anode and cathode solution was tested, and producing electricity process and energy utilization were analyzed to provide a theoretical basis for improving the MFC performance in this paper. Experimental results show as follows: The pH and ionic conductivity of the anode solution decreased, while that of the cathode solution increased with the MFC operation, and the latter was higher than the former by about 0.30?0.50 unit finally, while the average ionic conductivity of which changed slightly. When the MFC operated stably, the ohmic resistance was 29.69 Ω, the limiting current was 2.69 mA and the maximum power output was about 0.8 mW corresponding to the internal resistance of about 95.72 Ω. The mass transfer of potassium ferricyanide was the limiting factor of the limiting current. According to energy analysis, glucose of 91.1% in the anode solution was consumed by other microorganisms, and only glucose of 8.9% was used to generate electricity. Furthermore, the energy of 88.5% in the latter was converted into other forms, and only 11.5% of which was converted into electricity.

Abstract:Flavobacterium johnsoniae is capable of secreting enzymes which can efficiently hydrolyze yeast cell wall. Preliminary analysis revealed the presence of glucanase, chintinase and protease activities in its culture supernatant. A laminarinase was purified from the extracellular components of F. johnsoniae through several isolation steps including ion exchange, hydrophobic interaction and gel exclusion chromatography. The molecular weight of the purified laminarinase is about 35 kD. The optimum temperature and pH of its catalyzed hydrolysis are 50 °C and 5.0, respectively. Laminarin and laminari-oligosaccharide were hydrolyzed by this laminarinase in an endoglucanase mode with laminaritriose as the main product.

Abstract:To explore the suitable for Burkholderia cepacia plasmid elimination method and study the optimal conditions for plasmid elimination, we eliminated plasmid of Burkholderia cepacia T1828 by using sodium dodecyl sulfate and improving the growth temperature combination method, UV-coated plate method, freeze-thaw method, acridine orange method and baicalin extraction methods such as elimination methods. The results showed that sodium dodecyl sulfate and improving the growth temperature combination method is best suited to Burkholderia cepacia T1828 plasmid elimination, while the best conditions for the elimination are T1828 culture after 16 h by adding SDS to 0.1% of the final solubility dealt with 18 h at 36 °C, the elimination rate reach 49%. The plasmid-free mutant strains can be used for further study.

Abstract:Microcycle conidiation has been proposed as an advantageous?conidiation pattern for fungus with rapid propagation and strong resistance to stress factors. Deeply understand the microcycle conidiation mechanism will greatly enhance the potential of entomopathogenic fungi in biocontrol. Here, we isolated a microcycle conidiation associated gene, Pyk, in Metarhizium anisopliae and obtained its full length of DNA and cDNA sequence. Pyk gene in M. anisopliae encoded a homolog of pyruvate kinase with 583 amino acid residues, which showed a highly resemblance to that of other species in ascomycota (57%?77% identity). To clarify its role in microcycle conidiation, we constructed a Pyk-RNAi vector to knockdown Pyk transcript. RT-PCR demonstrated a reduced expression in mRNA level in three mutants. Furthermore, we analyzed suppression effect to Pyk in mutations. The mutants showed more varied shapes of conidia and less white hypha in colonial morphology compared to wild type.

Abstract:An endophytic bacterium isolated from Sophora alopecuroides in Xinjiang, which had a conspicuous antagonistic effect on methicillin-resistant Staphylococcus aureus (MRSA), was studied and bioactive substances were separated and purified. Strain KDNB6 was identified as Serratia marcescens by its morphological, physiological and biochemical properties and 16S rDNA sequences. An anti-MRSA active component produced in fermentation broth was separated and purified by silica gel column chromatography and sephadex gel column chromatography.

Abstract:Lots of endophytic bacteria strains isolated from healthy Sophora alopecuroides were studied by using surface spread plate experiment, confront antibiotic culture experiment, antagonistic activities of extracellular secretions determination and disease-control experiment in greenhouse. The results indicated that there were a lot of endophytic bacteria resources isolated from nodule of Sophora alopecuroides antagonized against Fusarium oxysporum. 48 strains with the relative inhibition rate more than 50% of total 60 endophytic bacteria were selected with surface spread plate method. 48 antagonistic strains were then screened in confront antibiotic culture trial. The results showed that 40 strains had inhibits against Fusarium oxysporum with more than 20 mm inhibition zone, and 26 strains with more than 5 mm in extracellular secretions inhibitory activities testing experiment on 40 antagonistic strains. In disease-control experiments with Fusarium oxysporum carried out in greenhouses, two isolates (KDRE12 and KDRE41) gave satisfactory results, with 67.11% and 72.65% average control effect, respectively, which have good applied potential.

Abstract:A novel ε-polylysine (ε-PL) producer with 0.846 g/L yield, designated strain Str-8, was screened from the soil collected from Guangdong, China, by using Nishikawa’s method with some improvement. Taxonomic identification of the strain, including morphology, culture characteristics, physiological and biochemical characters were performed and phylogenetic tree was constructed based on the 16S rDNA sequences, which indicated that it belongs to Streptomyces ahygroscopic. The purified fermentation product of this strain was identified as ε-PL by characteristic analysis, hydrolysate analysis, mass spectrum and UV spectrum.

Abstract:Designing the primers of hly gene by biological software, amplifying the hly gene from Listeria monocytogenes by PCR and constructing the gene into prokaryotic expression vector PET28a(+), then transforming the gene into E. coli BL21and expressing optimally; purifying the recombinant product LLO by nickel affinity chromatography, testing the immunogenicity by Western blotting and the hemolytic activity by hemolytic assay. It was demonstrated by agarose gel electrophoresis?that the cloned hly gene was 1 590 bp in length and the protein sequence got about 99% homology with that published in GenBank. SDS-PAGE indicated that the molecular weight was about 58 kD and the optimal expression condition was induced for 6 h with 0.1 mmol/L IPTG at the temprature of 28 °C. The result of Western blotting showed the recombinant protein LLO had immunogenicity. The hemolytic assay showed the product had the hemolytic activity, with the hemolytic titre of 1:1 024. These results would provide basis for the further studies on the development of monoclonal antibody against Listeria monocytogenes and the establishment of the dection methods.

Abstract:27 endophytic fungi were isolated from the barks and fruits of Camptotheca acuminate and then cultured in submerged fermentation. The fermentation products of each strain were analyzed with high performance liquid chromatography (HPLC) which showed that one produced camptothecin with the output of 774 μg/L. The strain was identified as Phomopsis sp. by phylogenetic analysis based on ITS rDNA and cultural and morphological characteristics. This was the first report that Phomopsis sp., which was isolated from Camptotheca acuminate, produced camptothecin.

Abstract:Endophytic fungi isolated from Polygonum cuspidatum in Qinba Mountains, China, were studied in this paper. Screening of metabolites in submerged cultures for these isolates by HPLC showed strain M-56 could produce polydatin with the yield of 1.029 mg/L. According to the morphological characteristics and ITS sequence, we identified the strain as Alternaria alternaria.

Abstract:One hundred and twenty-two bacteria strains were isolated from the intestinal tracts and body surface of five earthworms collected from four different provinces. Twelve fibrinolytic enzyme producing strains were screened based on the size of halo zone by using powdered skim milk and fibrous protein as the first and second round screening substrates, respectively. SC-3-W-3 strain with high fibrinolytic enzyme activity was identified as Bacillus cereus based on physiological and biochemical characteristics, as well as 16S rDNA. The fibrinolytic enzyme activity of SC-3-W-3 strain was up to 538.64 U/mL.

Abstract:Vibrio qinghaiensis sp. -Q67 was a newly identified luminescent bacterium in fresh water, its character of luminous intensity changed with toxic pollutant concentrations made it as an strain for water quality monitoring. Through bioassay strain JZA1 test, C18 reverse phase thin-layer chromatography and LacZ activity test, it was identified that Q67 had a LuxI-LuxR type Quorum-Sensing and produced N-acyl-homoserine lactone (AHL) as autoinducer. The other test results indicated that the content and activity of the signal molecular in Q67 changed with its growth phases. The crude extract from Q67 affected not only its luminescence but also its growth and reproduction.

Abstract:A microsphere-based LiquidChip assay was developed for rapid and simultaneous detection of Mycobacterium tuberculosis complex, Mycobacterium avium and Mycobacterium avium subsp. paratuberculosis (MAP). Four sets of oligonucleotide primers and probes which respectively targeted at IS6110, IS1081, IS1245 and F57 specific genes of mycobacterium were selected to establish the quadruplex assay. The quadruplex assay specifically identified target strains from a total of 54 strains of 13 species of mycobacterium, and 23 species of non-mycobacterium microorganisms were all detected as negative. The sensitivity on detecting cloned plasmid DNA by the quadruplex assay was 2.1×101?2.5×102 genomic copies or 0.06?0.74 fg DNA per reaction. The intra-assay and inter-assay variations of the quadruplex assays were both lower than 10%. The assay detected 75.6% (99/131) and 94.9% (37/39) positive from TB suspected human sputum samples and bovine tissue samples respectively, compared to culture methods that detected 38.9% and 53.8% positive from human and bovine samples respectively. The quadruplex assays also detected 24 MAP positive from 29 bovine blood specimens detected as positive by real time PCR specific for MAP. The tests on quadruplex mixed templates showed that the assay could identify mix infections. Clinical detection by the assay could be finished within one day, and the detection on purified DNA template could be completed in 2?3 h.

Abstract:In recent years, foodborne disease often occurred, even increased in some countries. Bacteriophages were originally used to treat bacterial diseases. Now people have realized that the application prospects of bacteriophages in the food industry are very wide. Bacteriophages have been used as the food additive to control food pathogens. The characteristics of bacteriophages illustrate that bacteriophages are the ideal tool to ensure food safety, because bacteriophages not only are safe and reliable, but also have strict host specificity which means bacteriophages don’t kill the fermentation strains in the process of controlling foodborne pathogens. Bacteriophages can be used in all aspects of food production to kill or inhibit pathogenic bacteria, such as raw materials collection, production, storage and others. In this review, we discuss the prospects and potential risks of bacteriophages in controlling foodborne pathogens.

Abstract:Pollution of soils and water with heavy metals is becoming one of the most severe environmental and human health hazards. Innovative ways are pressed for cleaning widespread heavy metals contamination. Phytoremediation is a remediation technology that requires the use of green plants to remove pollutants from the environment. Endophytic bacteria colonize within plant hosts without causing symptoms of infection or negative effects. The metal resistant endophytes are present in various hyperccumulatorplants. During phytoremediation of metals, the wild-type or engineered endophytes can lower metal phytotoxicity and enhance heavy metal translocation to plant through its metal-resistance system. Moreover, the metal resirtant endophytes can indirectly benefit plant growth by various mechanisms such as nitrogen fixation, solubilization of minerals production of phytohormines, siderophors, 1-aminocyclopropane-1-carboxylate (ACC) deaminase. This review describes the potential for exploiting plant-endophyte pertnerships to improve phytoremediation of heavy metals.

Abstract:In this paper, the characteristics and harm of food waste were briefly introduced. New resource recycling technologies of food waste with microbial technology were reviewed, including bio-decomposable plastic production, biological anaerobic fermentation, microbial composting, biopesticide production, bioelectricity generation. In addition, the research progress on microbial degradation of food waste was introduced and the prospect of this new technology was discussed.

Abstract:Peroxisome, an organelle with a single membrane, lies in various eukaryotic cells. Peroxisome contains more than 50 enzymes, involved in multiple physiological metabolic processes in organisms, such as the glyoxylate cycle, β-oxidation of fatty acid and regulation of active oxygen. Recently, increasing studies showed peroxisome influence on the glyoxylate cycle, β-oxidation of fatty acid, and pathogenicities of pathogenic fungi. In this review, types and functions of enzymes in peroxisome, metabolic processes related to peroxisome and relationship between peroxisome and pathogenicities of pathogenic fungi were summaried.

Abstract:It was presented about several reforms in teaching content and teaching mode of the enzyme engineering course for senior undergraduate students in biotechnology and bioengineering. The new teaching mode was that industry cases assisted the theory teaching of enzyme engineering, which included that new textbooks were chose in English and Chinese, teaching contents were renewed, industry cases assisted the theory teaching in the whole curriculum and theory section, and students participated in the interactive teaching classroom, etc. Better teaching effect was received by the teaching reforms.

Abstract:In this paper, we present our experiences on bilingual education of Food Hygiene and Detection course. Aiming to cultivate the management personnels and inspectors in food production system, we have focused on cultivating students’ comprehensive capability, such as interdisciplinary knowledge and international communication skills, during the course teaching process. Besides, we have established the teaching model of keeping pace with times, cultivating interdisciplinary ability, and implementing various practices and bilingual education. As a result, the students' self-directed learning ability and practical ability were promoted and their service consciousness and global visions were developed.

Abstract:PCR technology has been widely used in the detection of Vibrio parahaemolyticus. However, traditional PCR appeared higher false-positive result because of the lack of differentiation between DNA from viable and dead microorganisms. Therefore, Ethidium Monoazide Bromide (EMA) was added in the process of PCR to establish a rapid and accurate detection method of V. parahaemolyticus. The dnaJ gene was used as the target gene for PCR detection of V. parahaemolyticus by utilizing its pure isolates and genomic DNA as the template, and the sensitivity was 2.5×104 CFU/mL and 6×102 fg/μL respectively. The use of 5 mg/L or less EMA did not inhibit the PCR amplification of DNA derived from viable bacteria. The PCR amplification of DNA derived from 1×108 CFU/mL V. parahaemolyticus dead cells can be inhibited by 2 mg/L EMA. The results show that EMA-PCR can be used to minimize the false-positive results by inhibiting the PCR amplification of V. parahaemolyticus dead cells from a mixed bacterial population.