Abstract:

Abstract:Characters of one Candida intermedia yeast strain which isolated from nature can produce ethanol from xylose-fermenting been systemic studied. In conditions 28°C, 120 r/min, 72 h, it can produce 6.480 g/L ethanol from 7% xylose and 43.70% theoretical production of ethanol from 3% xylose. It can produce up to 21.225 g/L ethanol when incubation time prolong to 156 h from 8% xylose. It also can ferment 13% glucose produce 47.647 g/L ethanol and reach 76.90% of theoretical ethanol production, respectively. Compared to CK, ethanol productivity can be improved 9.91% when add 8% xylose in three times as 3%, 2% and 3%, respectively. Glucose can be first utilized in the mixture sugar medium. When the ratio of xylose vs. glucose is 3:1in mixture sugar, the productivity of ethanol can be improving 25%.

Abstract:The strain Acidiphilium cryptum DX1-1 producing PHB was irradiated respectively by UV and Co60 to raise PHB production. The results indicated that the effect of UV better than using Co60. One strain of the UV mutagenized called UV60-3 has the highest PHB production yield, showing final PHB concentration of 28.56 g/L, 1.45 times higher than that of original strain. FT-IR spectroscopy analysis shows that the polymers obtained from the strain DX1-1 have the same IR spectra of standard PHB. Further research about the best appropriate C/N ratio of the mutant was done. The optimum ratio of C/N was about 3.76, the final PHB concentration reaches to 30.57 g/L.

Abstract:The bioreactor production of recombinant Lateolabrax japonicus growth hormone (rljGH) expressed intracellularly by Pichia pastoris was investigated. A strategy of feeding methanol at the exponential rate was established and the effect of specific growth rate on the rljGH production was examined. The results indicated that the average specific production rate increased and the rljGH production duration decreased as the specific growth rate increased. The maximum specific rljGH production (0.58 mg/g WCW) was achieved at a specific growth rate of 0.029/h. The effect of supplementing ammonium sulfate, peptone and yeast extract on the rljGH production was further investigated. The results indicated that the effects of ammonium sulfate and peptone were not significant. Supplementing yeast extract of 2.5 g/L was advantageous for the rljGH production. The duration of the rljGH production was increased to 23 h from 17 h and the fermentation stability of run-to-run could be improved.

Abstract:Bacillus subtilis B6-1 was used as an original strain for mutagenic treatment and a defined medium was used as the selective medium. A mutant named B. subtilis W003 was isolated after three serial ultraviolet (UV) irradiations and one diethyl sulfate (DES) treatment. The γ-PGA yield on a rotary shaker was enhanced from 10.9 g/L in parental strain to 20.5 g/L in the mutant. It was illustrated by single factor experiments that the optimal carbon and nitrogen sources were glucose and (NH4)2SO4 respectively. The optimal fermentation medium was achieved by orthogonal test. In the optimal medium, a γ-PGA yield of 45.3 g/L was obtained after 36 h cultivation.

Abstract:The paper studied antibacterial effects in vitro of gelatin, nano-SiO2 and gelatin/nano-SiO2 composite membranes on 6 kinds of bacteria. The results indicated that gelatin had no antibacterial effect; nano-SiO2 had antibacterial effect; 11 out of 20 kinds of gelatin/nano-SiO2 composite membranes had strong antibacterial effects. Their minimal inhibitory concentrations (MICs) were also tested using the method of plate dilution, and the results indicated that they had different MICs because of different membranous formula and different bacteria. There were differences of MICs for different bacteria. For Bacillus cereu, MIC was 256.0 mg/mL; but for other bacteria, MICs were mainly 64.0 mg/mL-128.0 mg/mL.

Abstract:With reverse transcriptase PCR, the transcripton of copper homeostasis relative gene Afe0329 in Acidithiobacillus ferrooxians standard strain ATCC23270 was investigated. The further analysis of genes in this transcripton was analyzed employed by Vector NTI, Blast, TMHMM Server, PSORTb software and so on. From the DNA of different strains, the transcripton of Afe0329 was amplified using special primer pairs to identify the universality of it in the genome of A.ferrooxidans strains. The results showed that gene Afe0330 and Afe0331 were cotranscribed with Afe0329, and they were in a single transcripton. Gene Afe0329 was supported to express a P1b3-type ATPase which is a heavy metal ion pumping transmembrane protein, protein AFE0330 which expressed by gene Afe0330 was a cytoplasmic protein, no significant homologous sequences of Afe0330 or Afe0331 had been obtained by Blast analysis. And the transcripton of Afe0329 was universal in genome of A. ferrooxidans strains.

Abstract:By using gene SOEing PCR, Arg (CGC) in the expression fragment of chitinase gene (chi58) from Chaetomium cupreum was mutated synonymously to Arg (AGA), which is a bias code of Pichia pastoris yeast. The expression plasmid pPIC9K-chi58A was constructed and transformed into GS115 strain through electroporation. The chitinase activity reached 101.71 U/mL±3.33 U/mL after induced with 120 h, which was the 3 fold of the original strain (31.83 U/mL±4.85 U/mL). Additionally, recombinant yeast showed good genetic stability after 10 cycle. SDS-PAGE analysis suggested that the weight of protein was 58 kD.

Abstract:Actinobacterial diversity in samples of saline mines was investigated by constructing three actinobacterium-specific 16S rRNA gene clone libraries from Jiangcheng salt mine and Heijing brine pits. The primers for the Class Actinobacteria were used to construct the 16S rRNA gene clone libraries. At least 469 purified clones were digested with Hae III for RFLP analysis, in order to separate the clones into groups according to their restriction patterns. Among of them, 133 sequences were selected and determined for their partial 16S rRNA gene sequences. The result of phylogenetic and statistic analyses indicated that actinobac- terial OTUs were closely related to most members of the Class Actinobacteria, and some OTUs may represent some unknown groups. Heijing and Jiangcheng located in different saline places of Yunnan, China. However, the communities, species diversity of Actinobacteria and Phylogenetic relationship from the two saline mines were similar.

Abstract:An aerobic denitrifying bacterium H2 was selected from the pond sludge by using a new screening method: Samples were enriched by intermittent aeration firstly, secondly limiting diluted, then screened with BTB screening culture medium. Strain H2 was identified as Bacillus sp. according to its physiological and biochemical characters, as well as 16S rDNA sequence homology comparison. The highest degradation velocity of NO3- and NO2- were 0.46 mg/L×d and 0.885 mg/L×d, and the degradation rate of total nitrogen was 45.2% in aquarium water during the 15-day experiment. The study showed that strain H2 had great potential in the biodenitrification of aquaculture.

Abstract:Linear and circular plasmids were investigated among the 44 strains of the rice plant endophytic Streptomyces. By pulsed-field gel electrophoresis, 60 kb-410 kb linear plasmids were detected from the 8 strains and four of which might contain the conserved telomere replication gene tap, resembling that of soil Streptomyces strains, indicating that the diversity of Streptomyces linear plasmids was not affected by the unique environment of the rice plant. By alkaline method, 6 kb~60 kb circular plasmids were detected on gel from the 13 strains.

Abstract:A β-mannanase gene (TM_1227) from Thermotoga maritima MSB8 was cloned and expressed in E.coli. The recombinant β-mannanase was purified and characterized. The gene consists of 2010 bp, and the translated protein encodes 669 amino acids and its molecular mass is approximately 76.827 kD. Homology analysis of the deduced amino acid sequences showed that the enzyme shared 99% identity with β-mannanase from Thermotoga sp. RQ2. The mannanase activity was up to 39.7 U/mg after the recombinant E. coli BL21 was induced by IPTG. Crude enzyme solution was purified to homogeneity by Ni-NTA agarose. Its optimum temperature and pH was 95°C and pH 8.0 respectively for LBG. The enzyme remained over 50% activity after treated at 85°C for 30 min. The above properties showed great potential of its application in paper industry. The mannanase hydrolyzed copra mannan and LBG to give various sizes of oligosaccharides, and almost no mannose was detected by TLC, which was suitable for mannooligosaccharides production.

Abstract:We have studied the influence of ferric iron on the production of siderophore (microbial iron transport compound) from Pseudomonas sp. on universal CAS (Chrome azroul S) assay agar and modified sugar-aspartic acid (MSA) agar or liquid medium respectively. The results showed that the non-fluorescent siderophores (pyochelin) were produced on universal CAS assay agar and liquid medium and fluorescent siderophores (pyoverdine) on MSA agar and liquid medium; and the pyoverdine was more sensitive to the response of ferric iron whatever on agar plate or in liquid medium.

Abstract:Two endophytic-bacteria isolates of G18 and F19 were isolated from the stem of Taxus chinensis. The G18 and F19 were respectively classified into Psudomonas sp. and Stenotrophomonas sp. based on biological characteristics and 16S rDNA sequence analysis. The bioactivity analysis showed that the fermented broths of the G18 and F19 exhibited antagonistic activities against three pathogenic bacteria, and had good antagonistic effectiveness to Verticillium dahliae and Colletotrichum gloeosporioides, respectively. The G18 can degrade salicylic acid, and the F19 can do dichlorvos.

Abstract:SigE, encoded by sigE gene is an important sigma factor in the sporulation process. Many known genes and operons are controlled by this sporulation-specific factor, as well as most of cry genes in Bacillus thuringiensis. In this study, a sigE deletion mutant HD-73 (ΔsigE) was constructed by homologous recombination from Bacillus thuringiensis subsp. kurstaki HD-73 strain. The result showed that the mutant strain lost the ability of sporulation and crystallization of Cry protein. At the same time, the expression of insecticidal crystal proteins was severely reduced in HD-73 (ΔsigE) mutant, and growth speed of the mutant was affected intensively. The lacZ gene was fused with the promoter of the cry1Aa gene, and expressed in HD-73 (ΔsigE) mutant and HD-73 acrystalliferous mutant respectively. The activity of β-galactosidase expressed by lacZ gene in HD-73 (ΔsigE) mutant was much lower than that in the HD-73 acrystalliferous mutant. The ability of sporulation and crystallization of Cry protein was normally complemented by the expression of spoIIG operon, which contained the sigE gene after transformation with recombinant plasmid, and growth speed of the complemented strain also recovered. All the results indicated that for the B. thuringiensis subsp. Kurstaki strain, sigE gene is essential to sporulate and crystallize. Acquirement of HD-73 (ΔsigE) mutant will redound to understanding mechanism of Cry protein expression and regulation, crystallization and its relationship with sporulation.

Abstract:The glucose isomerase produced from Thermotoga maritima, a hyperthermophilic anaerobic bacterium, has a large potential in industrial application because of its excellent thermostability. T. maritima can only produce small amount glucose isomerase since the rigorous cultivation conditions. The gene xylA encoding glucose isomerase from T. maritima MSB8 were cloned and expressed in Escherichia coli JM109 using a heat-shock expression vector pHsh. The recombinant glucose isomerase was purified 8.02-fold from the E. coli JM109 recombinant with a recovery of 49.02% using heat treatment and ion exchange chromatography, to give a single band on SDS-PAGE. The optimum pH and temperature of the enzyme were found to be pH 7.0 and 95°C. The enzyme was stable in the range pH 6~9, and showed a half-life of over 5 h at 95°C. The enzyme activity was activated with 5mmol/L Mg2+ and Co2+. The apparent Km and Vmax values for glucose were 105 mmol/L and 45.2 mol/(min×mg), respectively.

Abstract:Endophytic bacteria reside in most healthy plants; it can not be easily influenced by outer environment. Some endophytic bacteria are beneficial to host plants, such as growth promotion, disease prevention and nitrogen fixation etc. Therefore, endophytic bacteria are the potential microbial fungicides, it may be widely applied. In this study, endophytic bacteria were isolated from soybean cultivar Hefeng 25 that was a main soybean cultivar in Heilongjiang province, China. The results indicated that the density of endophytic bacteria varied in different tissues of the plant. It was 3.4×103 CFU/g in roots, 2.8×103 CFU/g in leaves, 2.9×102 CFU/g in stems and 1.4×102 CFU/g in seeds. The activity of 121 strains against Fusarium oxysporum f. sp. soybean, caused soybean root rot, were assayed. 25.6% of them showed antagonistic activity against F. oxysporum f. sp. soybean. One of them, strain TF28 isolated from soybean roots could inhibit the growth of many fungal pathogens. The inhibitory rates against F. oxysporum from different plant species were 80.2%-96.7%. Based on the morphological, physiological and biochemical characteristics as well as the sequence of 16S rRNA, strain TF28 was identified as Bacillus amyloliquefaciens.

Abstract:Streptomyces sp. S506 is one of PGPR strains isolated from tomato rhizosphere. The optimum solid fermentation parameters were studied. According to the amount of alive cells and the rate of conidium production, the optimum parameters were obtained as follows: bran 100 g, mineral matter M-1 15 g, K2HPO4 0.3 g, NaCl 0.25 g, KNO3 0.1 g, CaCO3 0.8 g, natural pH, liquid seed age 84 h, inoculum volume 10%, fermentation temperature 30°C, the ratio of material to water is 10:6, fermentation time 60 h. Under the optimized conditions, the alive cells amount of S506 will reach to 8.27×109 CFU/g, and the number of conidium is 6.23×109 CFU/g.

Abstract:Fermentation property and kinetic analysis of the inhibition of in vitro growth of pathogenic Escherichia coli K88, O138 by Lactobacillus intestinalis isolated from porcine intestine mucus were investigated. The results of fermentation showed that L1 result in a pH of 3.90 within 12 h and a large amount of lactic acid production, with the concentration of 104.08 mmol/L. Kinetic analysis of the antibacterial activity of L1 metabolic product toward K88, O138 showed that CFUS display strong antibacterial activity toward K88, O138; the antibacterial activity of L1 CFUS was higher than the lactic acid control samples and was mainly due to the production of lactic acid; K88, O138 had the tolerance property toward pH 4.5.

Abstract:In order to study the regularity of shedding virus from infected SPF chickens and the formation of aerosol of H9N2 subtype AIV, SPF chickens were bred in a positive and negative pressure isolator. Aerosol samples were collected by AGI-30 (All Glass Impinger-30) extractor, and simultaneously trachea and cloaca samples were collected by tracheal swabs and cloacal swabs in different periods after challenged with viruses. The above-mentioned samples were detected by HI, Dot-ELISA and RT-PCR methods. The results indicated that aerosols were isolated from the 4 days to the 43 days after inoculation. It was proved that H9N2 subtype AIV could copy themselves in respiratory passage and cloaca, and then could formation of aerosols. AIV H9N2 subtype could be isolated from cloacal and tracheal swabs 3 days after inoculation and lasted for 45 days, viruses were detected from all infected SPF chickens on 7 days.

Abstract:The development survey of Extracellular Biopolymeric Flocculants (EBFs) and flocculant- producing bacteria were introduced; some EBFs discovered in recent years were listed with their properties and chemistry components. Components analyses and mechanisms of flocculation and the factors might influence the activity of EBFs were given emphasis to discuss, genetics and metabolic mechanism study on flocculant-producing bacteria were summarized in detail, and the development and study tendency of microbial flocculant were put forward.

Abstract:Many beneficial bioactive substances were produced by Paenibacillus polymyxa such as antibiotics, antimicrobial proteins, plant hormones and flocculants. These bioactive substances also could be produced by Paenibacillus polymyxa making it show excellent prospect in biological control of plant diseases, treatment of mankind and animals. This article summarizes research advances in Paenibacillus polymyxa and their bioactive substances.

Abstract:L-arabinose isomerase (L-AI) can isomerize L-arabinose and D-galactose into L-ribulose and D-tagatose, respectively, which is currently the most effective biological catalyst for D-tagatose production. The crystal structure of L-AI has been solved recently and its gene has been cloned, sequenced and overexpressed. L-AI improved by protein engineering will be the dominant enzyme for industrial production of D-tagatose. This paper reviewed researches on protein structure and function, properties and application in D-tagatose production of L-AI, and the long-term potential development of L-AI was prospected.

Abstract:Bacterial biofilm is a biopolymer matrix-enclosed bacterial population adherent to each other and surfaces or interfaces. The organisms within biofilms are notorious for their resistance towards antibiotics compared to their free-living planktonic counterparts. Consequently, biofilms are of significant importance to both clinical and veterinary science. However, although antibiotic resistance of bacteria are widely reported in animals, their association with biofilms is rarely discussed. The aim of this review is to look at the mechanism of antibiotic resistance of bacterial biofilms and discuss the relevance between antibiotic resistance of animal bacteria and biofilms, besides this article can be seen as a reference in studying antibiotic resistance in bacteria and guaranteeing the safety of animal products.

Abstract:Experiment teaching is a most important item of college teaching, and plays a vital and unexchangeable role to train students for their ability to practice and to innovate. To construct a feasible and scientific examination system of experiment teaching, will significantly help deepen the reformation of experiment teaching and improve the teaching quality. So according to the request for cultivating qualified application person, we preliminarily constitute the valuation system throughout the whole course and in the final, of theoretic examination and practice examination, and combined with students’ self-valuation and valuation from teachers. In fact, the system works well with a perfect effect.

Abstract:According to teaching request for medical microbiology, blended teaching mode basing network sources was practiced in the course of clinical medical specialty, i.e. 80% of total class hours was used to traditional classroom teaching, while 20% was used for network classroom teaching. The examination and questionnaire survey were conducted after the end of the course, and the result showed the teaching effect of Blended teaching mode was much better traditional classroom teaching. Furthermore, blended teaching mode was helpful for overcoming limitation in traditional classroom teaching and training the self-study ability of students.

Abstract:The backgrounds and principles of Exciting Sequence Pedagogics(ESP) were demonstrated. The applications for ESP in the Microbiology experiment teaching was elaborated in details from two aspects, the suitable system in the course contents and the inspiring measures to students in teaching courses. ESP was favorable to the development of scientific qualities.

Abstract:In order to improve the traditional teaching of microbiology experiments a new microbiology experiment curriculum system is to be established with the cultivating creative ability as central contents by adjusting teaching contents, reforming teaching system, enriching teaching methods, strengthening construction of teacher. This will help them to improve their ability of thinking independently and creatively as well as their practicing ability.

Abstract:A new experiment curriculum system of environmental microbiology was established centering on applied microbiology in environmental protection field and emphasizing on design and research experiments to motivate the students’ interests for the course, which helped them to improve their ability of thinking independently and creatively as well as their practicing ability.

Abstract:According to the characteristics of sludge samples from full-scale wastewater treatment bioreactors, the essential total DNA extraction method for most environmental samples, lysozyme-SDS-phenol/ chloroform method, was modified to improve sample pretreatment, intensify cell lysis and enhance the efficiency of impurity removal. Obtain a general total DNA extraction method for industrial sludge samples. Such a method was applied for total DNA extraction of sludge samples from several running full-scale anaerobic or aerobic bioreactors in Shijiazhuang, China. The results indicated that the modified method was suitable for all the sludge samples in this study, showing the satisfying generality. The extracted total DNA of all sludge samples were pure, with about 1.8 of A260/ A280 ratio. The method was also efficient; with average total DNA yield of over 0.7 mg/g and maximum yield of 0.85 mg/g. Moreover, all the extracted total DNA samples could serve as templates directly to amplify 16S rDNA by PCR. The PCR products could be separated well by denaturing gradient gel electrophoresis (DGGE) and the DGGE band patterns were clear enough to be used for further analysis. All these facts indicated that the total DNA extraction method provided in this study could meet the requirements of sludge samples research, from full-scale wastewater treatment bioreactors, using molecular biology technologies.

Abstract:The major product of microbial transformation of glycyrrhetinic acid by Mucor spinosus AS3.3450 has been identified as 7β-hydroxyglycyrrhetinic acid on the basis of its spectral data. 7β-hydroxyglycyrrhetinic acid was directly determined by HPLC. Methanol and ultra pure water containing 0.03% trifluoroacetic acid was used as the mobile phase on C18 column, the UV detection wavelength was 254 nm. The maximum transformation rate observed was 712 mg 7β-hydroxyglycyrrhetinic acid/g glycyrrhetinic acid on day 9 under 27°C, 160 r/min and substrate at a concentration of 130 mg/L. Results show that the content of 7β-hydroxyglycyrrhetinic acid indicates a good linearity under these conditions with a average recovery of 98.1% and a RSD of 2.37%.

Abstract:The MPN method was used to enumerate ammonia-oxidizing bacteria (AOB) in water and sediments of several shallow lakes. The suitable incubation time, medium types and substrate (ammonium sulphate) concentrations were studied. The results showed that, MPN values increased with the incubation time, reaching a stable maximum at some time stages, which was 40 days in all the samples for MSF medium. Among the three media used (XZ-AOB、MSF、SW), MSF give the highest MPN value. In addition, ammonium sulphate concentration in medium was an important factor affecting MPN estimation of AOB. Compared to AOB in lake sediments, AOB in lake water was more sensitive to ammonium sulphate concentration.

Abstract:The method for analysis and determination the cleavage of soybean sterol, in which the soybean sterol was degraded and the products androst-1,4-diene-,17-dione (ADD) and androst-4-ene-3,17-dion (AD) were developed by Liquid Chromatography-mass Spectrometry. The HPLC conditions adopted were: a Alltima ODS-2 column (250 mm×4.6 mm, 5 μm), a mobile phase consisted of menthanol - water (70:30), a flow rate of 1.0 mL/min, a room column temperature. and the detective wavelength was 244 nm.The ZMD Micromass electrospray ionization (ESI)-mass spectrometer was employed. In such conditions the corresponding HPLC chromatogram and MS spectrum were obtained. The method has a linear ranger of 0.01 mg/mL ~ 0.09 mg/mL, R2 =0.9999, the recoveries of ADD and AD were 102.6% and 105.90%, the RSD of ADD and AD were 3.02%, 3.5% and 3.08%, 3.24%. This method showed high sensitivity, accuracy and easy to perform. It is suitable to analysis the process cleavage of soybean sterol as well as quality control of product.