Abstract:

Abstract:By using enrichment culture in liquid minimal medium or direct culture on minimal medium plates, thirteen bacterial strains (AD27-AD39) capable of utilizing atrazine as a sole nitrogen source for growth were isolated from a mixture of industrial wastewater and sludge from an atrazine manufacturing plant. Based on 16S rRNA gene sequencing, eleven strains were identified as Arthrobacter spp. and two strans were identified as Pseudomonas spp.. We further studied in detail the composition of atrazine-degrading genes and degradation characteristics of Arthrobacter sp. AD30 and Pseudomonas sp. AD39 that have high degradative activity. From PCR assays, it was indicated that both AD30 and AD39 strains contained atrazine-degrading genes trzN and atzBC and was capable of degrading toxic atrazine to nontoxic cyanuric acid. The biodegradation experiments showed that the percentage of atrazine removal were 92.5%, 97.9% and 99.6% respectively after AD30, AD39 or the mixture of the two strains were inoculated and incubated at 30°C for 48 hours in minimal media containing 200 mg/L atrazine, indicating that atrazine degradation by the mixed bacteria was more effective than the single strain. In addition, after industrial wastewater containing 176 mg/L atrazine was inoculated with the mixed bacteria and incubated at 30°C with shaking for 72 hours atrazine were removed by 99.1%, implicating that the mixed bacteria are good candidate for biotreatment of atrazine-containing industrial wastewater.

Abstract:Immobilization conditions of Candida tropicalis to be absorbed in polyurethane foam carrier materials were studied on the xylitol production from corn hemicellulosic hydrolysate. Optimum batch-fermentation conditions were as follows: inoculum amount, 7% (volume ratio); polyurethane foam quantity, 1.0 g/100 mL; 30°C; initial pH, 6.0. Shaking speed was divided into two-phase to accommodate the dissolved oxygen, with 200 r/min at 0~24 h and 150 r/min at 24 h~46 h. The immobilized cells on polyurethane foam carrier have high density and good resistance to inhibitors in the hydrolysates. Average xylitol yield and volumetric productivity of polyurethane foam immobilized fermentation were much higher than the fermentation without immobilization. Corn cob hydrolysates can be directly biotransformed to xylitol without decoloration or ion-exchange treatment. This process can effectively reduce production costs, and it shows broad prospects of applications. Average xylitol yield was 67.6% and xylitol volumetric productivity was 1.92 g/(L·h).

Abstract:An extracelluar amylase production extremely halophilic archaen was isolated from a salt ore of Yipinglang of Yunnan province. Based on the morphology, characteristics of biologic and chemical and analyzing of 16S rRNA sequence, the strain was identified as genus of Halorubrum, and named Halorubrum sp. CY. The rude characteristics of the extracelluar amylase determined. It had optimal activity at pH 6.0 and 60oC. Zn2+, Cu2+, Al3+, SO32- could promoted the activity of amylase and Mn2+ might inhibit the activity of extracelluar amylase.

Abstract:According to morphological and microscopic characteristics, a high-efficient decolorizing fungus, the strain Asaw117, was identified as Aspergillus awamori. Selecting eight different dyes from Azo dyes, anthraquinones dyes and oxygen Quinones dyes, the decolorizing assays of various dyes showed that the strain Asaw 117 was the highest decolorizing potential to 0.1 g/L Vat Blue RSN, the discoloration rate up to 100 percent. Comparing to different kinds of medium and several of carbon and nitrogen sources, the strain had the best decolorizing efficient although grew slower in the Czapek medium, otherwise, grew quicker and decolorizing efficient lower in the PDF medium. It could use Vat Blue RSN as a nitrogen source, but not as a carbon source. The medium composing of saccharose and ammonium nitrate as carbon and nitrogen sources was decolorizing potential markedly during different combinations of carbon and nitrogen sources. So the strain has good potential for the dyeing wastewater treatment.

Abstract:Several aquatic species and their enviroments were examined for presence of Vibrio parahaemolyticus between 2007 and 2008 in the coastal areas in Zhejiang province, and some virulence-related genes such as tdh, trh, ureC and vscC2 were investigated from the isolates. V. parahaemolyticus was recovered from 70% of the samples tested (395/566). The genes tdh, trh and ureC existed in 10.1%, 20.0% and 11.1% respectively from 395 isolates. Among the 40 tdh-positive isolates, 32.5% harbored the vscC2 gene, one of the type three secretion system 2 (T3SS2) gene family. Thirty-eight of the 40 tdh-positive isolates were positive for the Kanagawa phenomenon. Out of 44 trh-and-ureC-positive isolates, only six exhibited urease phenotype. Overall, this study reveals the significant prevalence of Vibrio parahaemolyticus in seafoods and their habitats with high diversity of virulence genes. Representative V. parahaemolyticus isolates could be used for further investigation into their pathongenecity, functional genomics, and molecular evolution.

Abstract:Salmonella enterica serovar Cerro 87, which was isolated from a commercial egg-producing farm, has a phosphorothioated DNA backbone resulting DNA degradation(Dnd) during the

Abstract:Strain 13-1 was gram negative biocontrol bacterial strains isolated from Amorphophallus konjac. In vitro antagonistic assay showed that strain could suppress the growth of seven plant bacterial pathogens and eight pant fungal pathogens. The results of phenotypic and general physiological and biochemical properties showed that strain 13-1 homologized with which descripted for genus Lysobcter. 16S rDNA determination and analysis was used for further identification, which showed that 16S rDNA sequence of strain 13-1 shared 99% homologies with published sequence of L.antibioticus DSM2044 from GenBank, and both sequences constituted a branch in phylogenetic tree. Based on these results, it is considered that the strain 13-1 belongs to one strain of L.antibioticus.

Abstract:PcoI-PcoR is a quorum-sensing (QS) system influencing the biofilm formation and rhizosphere colonization in Pseudomonas fluorescens 2P24. The expression of the pcoI, a N-acyl-homoserne lactone (AHL) biosynthase gene, is under the regulation of a number of chromosomal factors, such as the GacS-GacA two-component system. In this paper, we investigated the upstream regulators that influence the transcription of pcoI gene using a chromosomal pcoI-lacZ fusion reporter strain PM203. Cosmids containing genomic DNA of the wild-type strain 2P24 were introduced into the reporter strain PM203 (gacA—, pcoI-lacZ) to screen positive transcriptional regulators of pcoI gene. One of them named pP32-24, which contained a 5-kb Pst I functional fragment was selected. Further analysis identified that the pcoI was the gene responsible for the increase of the pcoI-lacZ expression. The expression of pcoI-lacZ reporter was also improved in both PM101 (pcoI-lacZ) and its gacA- mutant PM203 after addition of exogenous AHL, indicating that the expression of pcoI is positively regulated by AHL (autoinduction) in strain 2P24. In addition, deletion mutagenesis and complementation experiments demonstrated that the transcriptional regulator PcoR positively controlled the expression of pcoI and the formation of biofilm. These results suggest that, in strain 2P24, the expression of PcoI-PcoR QS system is auto-inducted, and the transcriptional factor PcoR is involved in the regulation of pcoI transcription and the biofilm formation.

Abstract:An endophytic bacterium strain EBS05 from Cinamonum camphra was identified as Bacillus subtilis by morphological taxonomy and sequence analysis of 16S~23S rRNA intergenic spacer regions. Properties of antimicrobial compound produced by EBS05 were assayed. The active compound had the maximum absorbance peak at λ213.5 nm. The antimicrobial activity was stable in solution with pH value from 5 to 8, and decreased significantly in solution with pH value less than 4.0 or more than 9.0. The antimicrobial compound had thermodynamics stability. Its activity changed a little after treated at 60°C~80°C for two hours, and compared with 65% original activity after treated at 1×105 Pa for 30 minutes. The active substance had high resistance to ultraviolet radiation and protease K. Antimicrobial compound was soluble in alcohol solution, which was easily dissolved in methanol and ethanol, but not dissolved in ethyl acetate, acetonitrile and petroleum et al.

Abstract:45 strains of Lactobacillus were isolated from 17 samples of traditional fermented milk in Gobi region of Mongolia. Based on morphological, physiological, biochemistry test and 16S rDNA sequencing analysis, identified as 31 strains of Lactobacillus fermentum(L. fermentum), 12 strains of L. helveticus, one strain of L. plantarum and 1 strain of L. casei. Survival rate of IMAU20085 is 81.44% in the screening experiment of resistance to the artificial gastric juice (pH 3.0). The isolation and identification of these strains and the screening of high acid-tolerant strains have important meaning to the preservation and exploitation of probiotic resource.

Abstract:A bacteriocin-like substance producing strain T12 was screened from 212 lactic acid bacteria isolated from intestine of healthy pigs by paper disk test and was identified as Lactobacillus. The supernatant of T12 exhibited strong inhibitory activity against the gram-positive bacteria, including Micrococcus lysodeikticus, Staphylococcus aureus, Bacillus subtilis and Bacillus cereus. A strong activity was also observed against the gram–negative bacteria and some eumycete, such as Escherichia coli, Salmonella typhimurium and Fusarium graminearum. Through detection of its appearance, physiological and biochemical characteristics and 16S rDNA gene sequence homology analysis, it was identified as Lactobacillus animalis. Eliminated the organic acids and hydrogen peroxide the fermented production exhibited strong inhibitory activity against indicat bacterias still; the inhibitory activity was totally lost after treatment with protease; The bacteriocin-like substance was heat-stable even at the autoclaving temperature (121°C for 20 min) and was active over a wide pH range (3.5~5.5). The protein nature and restricted spectrum of the substance points to its being bacteriocin-like substance.

Abstract:In this study, plate transparent circle by Davis method was introduce firstly screening α-Rhamnosidase high-yield strain. The spore-sprouted Aspergillus niger 8-hour were mutagenized by ethyl methane sulphonate and pre-screened via transparent circle. 11% mutants yield 40% higher of α-rhamnosidase than the original strain. A high-yield strain, T-226 with the highest α-rhamnosidase activity of 373.4 U/mL was finally selected from these potential high-yield mutants after rescreened by shake flask fermentation twice. When the T-226 strain was fermented in 5 L bioreactor, the enzyme activity could reach to 631.9 U/mL after 84 h. Thus, the established screening method is highly efficient to isolate α-rhamnosidase high-yield mutant of A. niger.

Abstract:Tuber F. H. Wigg. is an ecologically and economically important ectomycorrhizal ascomycetes that produce subterranean ascomata known as truffles. Some species in this genus are widely appreciated for their organoleptic properties. Their taxonomy, systematics, ecology, biochemistry and cultivation have been studied and great advance have been achieved. In this paper, the research history and recent advance on above aspects were summarized. Also, special proposal for further studies was also commented and recommended.

Abstract:At the time of phage’s discovery, phage therapy was regarded as a possible treatment method against bacterial infection. Although phage therapy was used to treat and prevent bacterial infection in the former Soviet Union and Eastern Europe, it was abandoned by the West in the 1940s with the arrival of the antibiotic era. However, the ongoing evolution of bacterial multidrug-resistance has recently motivated the Western scientific community to reevaluate phage therapy for bacterial infections that are incurable by conventional chemotherapy. With the in-depth study of phages, it’s increasingly acknowledged that phages, as the medicine to cure bacterial infection, are convenient, safe and efficient therapeutics. This paper summarizes the recent years’ advanced researches in this area.

Abstract:Small non-coding RNA (sRNA) is a kind of newly discovered 50 nt~500 nt small RNAs that do not encode proteins. To date, more than 150 sRNA have been found in bacteria. The small RNA acting by base-pairing with target mRNAs, resulting in post-transcriptionally regulating gene expression, is important regulators in the bacterial response to stress, virulence and metabolism. At present, researches of sRNA mainly based on bioinformatical prediction and molecular biological experiments. The sRNA that obtained through these methods needs confirmation in laboratory, and then study of its functions through a variety of experimental methods.

Abstract:Molecular methods and fluoroscopic techniques suggest that rich microbial diversity exist in the marine environment, but less than 1% of these microbes can be cultured in the laboratory conditions, and that the cultivable dominant species were even less. This limitation has long been a barrier to the development of environmental microbiology and the utilization of marine resources. In the past decade, novel methods for culture and detection of these uncultured marine microbes have successfully applied to obtain several conventionally-uncultured microbes including those from extreme environments. Those progresses have inspired researchers greatly. Developments in the research of marine microbial resources are an important basis for the study of the micro-world and deserve increasing scientific attention.

Abstract:Sulfate-reducing bacteria (SRB) are widespread in the environment. SRB are obligate anaerobes and capable of dissimilatory reduction of sulfate. SRB have application prospects in the control of environmental pollution due to that many pollutants can be removed by SRB. The biological characteristics and metabolic mechanisms of SRB are introduced, and the application of SRB in the treatment of environmental pollution is described in this paper. The research progress of Cr(Ⅵ) reduction and Cr(Ⅵ) removal from wastewater by SRB is reviewed, and future direction of research on the control of Cr(Ⅵ) pollution by SRB is also analysed.

Abstract:Biological process is an important approach to treat the dye wastewater. The azo dyes decolouration by special azoreductase of different aerobic bacteria and fungi was summarized. Under anaerobic condition, reductive decolourization of azo dyes was carried in the presence of redox mediators which act as electron shuttle. It was also pointed out that azo dye reduction occurred mainly under anaerobic condition. Different electron donor resulted in different decolourization rate. Problems of current biotechnology were analyzed and corresponding measures were discussed.

Abstract:The finding of dissimilatory nitrate reductase in fungi breaks the traditional concept that denitrification has been considered to only occur in a prokaryotic cell. Dissimilatory nitrate reduction in fungi includes denitrification and ammonia fermentation, which occurs under the conditions of limited aeration. Nitrate and nitrite can induce denitrification-related enzymes, which include nitrate reductase, nitrite reductase and nitric oxide reductase. Nitrate reductase and nitrite reductase exists in mitochondria, and enzymatic reactions they catalyze are coupled with ATP generation through ATP synthase in the respiratory chain and produce nitric oxide(NO). In contrast to the two enzymes, NO reductase uses NADH as the direct electron donor and thus might function in the regeneration of NAD+ and detoxification of the toxic radical, NO. Ammonia fermentation can reduce nitrate to ammonium and couples acetogenic reaction with substrate-level phosphorylation. In this review, the latest progress about the involved main enzymes, their gene expression regulation, and the comparison of the dissimilatory nitrate reduction between fungi and bacteria were discussed.

Abstract:It has evolved as a main limiting factor for the exploitation and application of microbial resources that more than 99% of microorganisms in natural environments cannot be cultivated so far by current isolation and culture methods. Metagenomics is an advanced methodology by means of extracting all microbial genomic DNAs in certain environmental habitat, constructing and screening metagenomic libraries to seek novel functional genes and/or biologically active compounds. It can overcome the advantages of isolation and cultivation procedures in traditional microbial method, and thus greatly broaden the space of microbial resource utilization. So it has become one of the powerful research tools for microbiology, biotechnology, soil and environmental sciences, and a new field of genetic engineering. This paper mainly reviewed the metagenomic methodology including genomic DNA isolation, library construction and screening strategies. And this review also outlined the up-to-date applications of metagenomics in various fields.

Abstract:Trehalose is a naturally occurring non-reducing disaccharide. This sugar has been known as a protector of biomembrane and macromolecules. And it has been widely used in foods, medicines, cosmetics. Trehalose synthase (TreS) is an intramolecular transglycosylase. It can catalyze the conversion of maltose into trehalose in one step. As the simple protocol and cheap substrate, it is very prospect in the industrial production. Here we have discussed the properties, catalytic mechanism and gene-engineering of TreS, and also proposed some solutions to its present research problems.

Abstract:According to the characteristics of practical teaching of microbiology and starting from the reformation of experimental outline and management style, we have preliminarily constructed the management model of a microbiological open laboratory in the aspects of space, apparatus, experimental time, content, etc. And we have obtained good results in practice.

Abstract:A set of teaching methods have been explored and practiced in this paper, which include paying attention to knowledge originating process teaching, enhancing thought training, constructing microbiology knowledge system, concerning reality, following the advanced achievement during the microbiology class teaching process, in order to improve teaching quality overall, cultivate students’ innovative ability.

Abstract:This article introduced the development and application effect appraisal of Microbial Engineering CAI courseware for bio-engineering specialization. The courseware focuses on knowledge system integrity, content-rich and gives prominence to the key points. Pictures, animation and video, and audio effects are also utilized appropriately to achieving stimulate students interest in learning and then improve teaching and learning performance. The courseware concentrates on core content of the course, such as fermentation parameters detection and automatic control, and fermentation equipments. The courseware was manufactured using the Powerpoint software. Animation was established with Flash 4 software and the scanning pattern was edited using Adobe photoshop. And chapters of the courseware were composed and administrated using Courseware Master Software. A two-year survey showed that 85% of students satisfied with this courseware.

Abstract:Biolog EcoPlateTM is a mainstream approach of studying community-level physiological profiles of microbes. To correct misunderstanding and insufficiency of experimental result explanation, we announced an amendment of information extraction of Biolog EcoPlateTM, which included two parts: (1) carbon substrates assortment sheets based on microbial physiological metabolism and ecological function, providing referrence and index for researchers; (2) illustration of how to use assorment sheet and ordination method to find out more information, guiding by environmental concentration principle.

Abstract:Pseudomonas sp. M18 is one of plant growth-promoting rhizobacteria capable of producing two kinds of anti-fungal agents: phenazine-1-carboxilic acid (PCA) and pyoluteorin (Plt). The pqsR gene, which encodes a LysR family member PqsR, was amplified from chromosomal genome of strain M18. Using the homologous recombination technique, a chromosomal pqsR inactivated mutant strain M18PRG was constructed in Pseudomonas sp. M18. To study the effect of pqsR gene on Plt biosynthesis, the dynamic curves of Plt production by strains M18 and M18PRG was measured in KMB media. As a result, Plt production of the pqsR mutant was three to four folds higher than that of its parent strain M18. The Plt production was restored to the wild-type level when strain M18PRG was complemented with pqsR gene in trans. The regulation of pqsR gene on Plt production was further confirmed by the pltA′-′lacZ translational fusion analysis. These results indicate that pqsR gene negatively controls the Plt biosynthesis. Additionally, by analyzing the growth curves of wild type strain M18 and pqsR mutant, we can readily find that PqsR has a negative influence on cell growth. It was also shown that the production of red pigments in strain M18 required the expression of pqsR gene. In conclusion, the data presented in this study clearly demonstrate that PqsR acts as a global regulator involved in many physiological activities in Pseudomonas sp. M18.