Abstract:Lactic acid bacteria(LAB) has been widely used in food industry for centuries.In recent decades,the LAB food-grade expression systems have been established and developed since the potential use of these bacteria as homologous and heterlogous protein expression hosts has been investigated extensively.Here we briefly introduced the basic conditions and principles of the LAB food-grade expression systems,we also summarized and tracked its lastest application development.According to the location of the LAB food-grade expression systems in the food economy,We prospect its application foreground in the areas as follows:food industry,medicine and health protection.

Abstract:With sensory characteristics,physical index(whitness,hardness,stress),microbiological(total viable count) as parameters,the effects of tea polyphenols(0.4 g/dL) and phytic acid(0.04 g/dL) on the quality of fish ball during cold storage were examined.It was found that the shelf life of treatment was increased 14 d during storage at-2±0.5.At the end of shelf life(35 d),the total viable count of the treated group decreased to 3.51 lgCFU/g(the control is 6.3 lgCFU/g),the Whiteness was 85.21 and 86.12,spinginess was 0.88 and 0.86,hardness was 576.43 and 500,senerory attribute value was 3.76 and 2.73,and the water loss was 6.63% and 7.93%,respectivly.Based on the aboved results,it was suggested that the compound bio-preservative had great effects on the propagation of bacteria and improvement of sensory quality,which prolonged signigicantly the preservation time of fish ball.

Abstract:S-adenosyl-L-methionine(SAM) was high-value amino acid that had great market potential.To enhance SAM accumulation by inhibiting its consumption,three inhibitors were added during the late fermentation stage of inducible Pichia and constitutive Pichia.Firstly,their influences were investigated,and the differences were compared,and finally,the mechanisms were analyzed.The results showed that addition of Aristeromycin,an inhibitor of S-adenosyl-L-homocysteine hydrolase,contributed to SAM accumulation,but comparatively speaking,the optimum addition level for inducible Pichia was lower,likely because the oxidative stress resulting from methanol metabolism strengthened the dependence of Pichia cell on transmethylation reaction.Supplement of DFMA,an inhibitor of polyamine synthesis,improved SAM accumulation,while the excessive amount of DFMA led to reduction of cell growth and anti-oxidation ability.Addition of acetic acid at 7.5 g/L improved SAM accumulation,through reducing polyamine formation.The three inhibitors mentioned above were proved effective for improvement of SAM production.

Abstract:In this study,the nutritional and environmental conditions of white-rot fungi,Trametes hirsuta SYBC-L19,for laccase production were investigated and optimized though single factor experiments and response surface methodology.The optimum conditions described as follows:water hyacinth(dry weight) 41.0 g/L,corn steep powder 50.8 g/L,glucose 30.0 g/L,CuSO4·5H2O 0.6 g/L,tween-80 0.5 g/L,vanilline 0.5 mmol/L,inorganic salt mixture 50 mL/L,inoculation concentration 8%,pH 4.0,liquid volume 80 mL/250 mL,culture temperature 30 ℃.With the conditions,the activity of laccase was achieved at 7 784 U/L,was higher 17.3 times than that of control.The study provides a path and a certain theoretical basis for effective utilization of the water hyacinth and other biomass resource.

Abstract:In order to overexpress the Rhizomucor miehei Lipase(RML) gene and obtain a large number of bioactive proteins in Escherichia coli.Firstly,the research improved the amount of the soluble protein through three methods:1) RML was introduced at 16 ℃.2) RML was fused with a new chaperone(Skp) which was located at the N terminal of RML;3) RML was fused with the Trx.tag in pET32a and the tag was located at the N terminal of RML.Secondly,the specific activity of purified RML derived from different methods was detected as(226±10~247±10) U/mg.The expression result showed that the low-temperature inducing was best method and the concentration of RML was 0.86 mg/mL.It was proposed that the temperature was the key factor of controling the amount of soluble protein.The activity test showed that fusion of Skp/Trx·tag and the N terminal of RML did not change the activity center(C terminal) and the catalytic ability of RML.Therefore,the strategy for overexpression of RML in E.coli kept the biologycal activity and was valuble in the practice.

Abstract:The engineering pichia pastorios GS115 is constructed which express recombinant human serum albumin and interferon-alpha2b fusion protein.The fermentation conditions are optimized in flask and 5 L fermentor.The surpernatant was purified by Blue Sepharose 6FF affinity chromatography,Phenyl Sepharose 6FF hydrophobic chromatography and Q Sepharose 6FF ion-exchange chromatography.The purified protein was detected by SDS-PAGE,molecular weight determination,nitrogen terminal sequence,endotoxin determination and anti-virus biological activity detection.The fermentation technology condition is stable and the harvest can reach 350 mg/L.The purity of purification protein is more than 95%.Molecular weight is 85 820.9 Da and amino acid sequence of nitrogen terminal is DAHKSEVAHRFKDLG.The result is correspond to the expected.The endotoxin is less than 5 EU/mg,which meet the standard requirement.The anti-virus activity of the protein is 1.6×106 IU/mg by bio-assay.It has excellent properties for industrial applications.

Abstract:Three kinds of processing technologies of Lentinus edodes chips were studied in this manuscript..the parameters including colors,crisp extents,energy consumption,shape and flavour amomg vacuum fried chips,vacuum microwave chips and vacuum drying chips were compared to determine theoptimum pretreatment conditions,and listed as follows:temperature(95±2) ℃,blanching time 2~3 min,color fixative 0.01~0.02 g/dL EDTA-2Na and 0.3 g/dL citric acid.

Abstract:Curdlan is water-insoluble polysaccharides from Agrobacterium sp.ATCC 31749 after cell growth has ceased due to nitrogen exhaustion.The involvement of nitrogen regulatory systems in curdlan production is not surprising,but the mechanism is not known.To explore homeostatic responses to N limitation and the relationships between nitrogen regulation protein NtrC and curdlan synthesis,differences of expression level between Agrobacterium sp.ATCC 31749 and the ntrC mutant under nitrogen sufficient and nitrogen limitation were correlated by real-time PCR.For Agrobacterium sp.ATCC 31749 wild type,four nitrogen metabolism-associated genes(ntrB,glnA,glnB,nifR)and six carbon metabolism-associated genes(exoC,exoN,crd,cisY,ndk,glmU)relative expression level were improved differently under nitrogen limitation.The results indicated that Agrobacterium sp.regulated the whole celluar metabolism(nitrogen assimilation、carbon metabolism and energy metabolism etc.) and channeled the carbon flux into curdlan synthesis for energy storage under adverse condition.NtrC protein was involved in regulating curdlan production,and curdlan synthesis-associated enzymes were regulated at not only transcriptional level but also translational level.Curdlan synthesis capacity of the ntrC mutant decreased severely while relative expression level of the crd gene increased as compared to the wild type under nitrogen-limited conditions.It is speculated that the NtrC protein may not be transcription factor of the crd gene.

Abstract:The objective of this study was to investigate the diversity of culturable yeast strains from permafrost soils at the terminus of a glacier in the Tianshan Mountains was investigated.Isolation and molecular phylogenetic analysis were performed in order to expand our knowledge on diversity of psychrotrophic and psychrophilic yeast.In addition,efforts focused on screening for psychrophilic yeast.Psychrophilic yeast strains were detected on YEPG plates,respectively.Identity and genetic diversity of strains isolated was determined by 26S rRNA gene D1/D2 by the forward primers NL1 and the reverse NL4.The physiological tests were carried out to determine the phonotypic differences between strains showing high similarity of 26S rRNA gene sequences.In all,4 yeast stains was isolated by 26S rRNA gene D1/D2 and internal transcribed spacers of 4 genera(Cryptococcus,Sporobolomyces,Clavispora,Pichia).The results enrich our knowledge on the differences of psychrotrophic yeast diversity between the glacier under study and other worldwide cold habitats are also discussed.

Abstract:In order to improve the degree of hydrolysis of horseradish in Japanese horseradish,to improve the product quality of Japanese horseradish,we use the horseradish powder as the raw materials to process Japanese horseradish,in that process to study the degeree of hydrolysis.We studied the temperature,time,pH and the amount of ascorbic acid(VC) as the four factors to impact the degree of hydrolysis,the results show:optimal conditions were temperature 60 ℃,time 1 hour,the pH value of 4.0,addition of ascorbic acid(VC) 0.2 mg/g.Provide a reference to further enhance the degree of hydrolysis of horseradish.

Abstract:A specific and sensitive SYBR Green real-time fluorescence PCR method was developed to determine of the shark derived material in food.The specificity and sentivity of this method was examined.The results showed 9 kinds of shark samples displayed theamplified curves and the highest point of melt curves at(84±1.5) ℃,whereas other 48 kinds of common plants and animals displayed no amplified curves and the highest point of melt curves at temperatures out of(84±1.5) ℃.The detection limit of the method was 0.000 1 ng/μL DNA and 0.01% shark meat powder.The 20 commercial shark products samples were analysized by SYBR Green PCR and all the products indicated existence of shark DNA except the artifical shark fin and shark liver oil.The results indicated that the detection method is highly specific and sensitive,and can be used to the identification of shark derived material in food.

Abstract:In order to investigate the preservation effects of glycyrrhiza or forsythia extracts and their complex liquids on peach fruit,the physiological and biochemical characteristics of peaches were determined after 5 min treatment by the extracts of glycyrrhiza,forsythia,and their complex liquids.The proportions of complex liquids were glycyrrhiza:forsythia=3∶1,1∶3,1∶1.The control was distilled water.The results showed that:compared to the control,the preservation effects of peaches were improved by different chinese herbal extracts.After treated with glycyrrhiza extract and glycyrrhiza:forsythia=1∶1 complex extract,the weight loss rate and respiration of peach were decreased significantly(P<0.05).And the mass fraction of SSC and TA were mitigated.Treated with glycyrrhiza extract and glycyrrhiza:forsythia=1∶1 complex extract,the increase of MDA was inhibited,the high mass fraction of Vc was maintenanced.The commodity value of peach fruits was keeped,and compared to the CK,the storage period of peach was prolonged 2 days.

Abstract:Research of screening and fermentation about Bacillus sp.as the protease producing strain is extremely necessary due to their characteristics of heat and pH stability.In this study,strain with producing alkaline protease was screened from the offshore soil of Yantai and the morphological,physiological and biochemical characteristics as well as 16S rDNA sequence homology of the isolation were studied.From the above characteristics,the strain was identified as Bacillus amyloliquefaciens.For industrial production of protease,the optimum nutrition and environmental conditions were determined.Under the optimum conditions,the maximum protease activity reached at 395.18 U/mL at 18 h,which was about 2.55 fold higher than that of the the original medium.The study provides reference data for further industrial fermentation production of alkaline protease.

Abstract:In this manuscript,the peeled litchi was dried by hot air drying,hot air microwave coupling drying,microwave vacuum drying and vacuum freeze-drying.The index including protein content,the reducing sugars concentration and colour were compared in the four drying methods.It was found that different drying methods should be chosen according to the different formations on different conditions.

Abstract:It combined the gravimetric method with HPLC to detect different kinds of pectin in the tobacco stems and cut-stems after enzymatic.Firstly,the sample of tobacco stems and cut-stems after enzymatic should be treated by acid hydrolysis and filteration.Then we detected the content of calcium pectinate in the solid samples by gravimetric method.The galacturonic acid in the supernatant that was discarded in the process of sample treatment will be tested by HPLC.These two parts of the content of pectin could be conversed and added together.The analytical results showed that the coefficient of variation was 0.33%,the average recovery of galacturonic acid was 99.32%.Using this method,the coefficient of variation of the content of the total pectin acid was lower than traditional gravimetric method.The pectin would be fully extracted.The detection method is comprehensive and with good reproducibility,and easy operations.

Abstract:In this manuscript,the effect of carbon sources on the mycelium growth of Ganoderma atrum in submerged fermentation was studied by orthogonal experiment.furthermore,the the interactions of inorganic salt,vitamin and carbon source were also discussed.The main results was obtained and listed as follows:1) fructose was much better than that of sucrose and lactose on mycelium reproduction,and the demands for inorganic salt and vitamin were dependent on the kinds of carbon sources;2) the optimum medium for mycelium was 20 g/L fructose,2 g/L KH2PO4,2 g/L K2HPO4,2 g/L MgSO4·7H2O,1 g/L CaCl2·2H2O,20 mg/L VB1,natural pH.with the optimum medium,the the mycelium biomass of G.atrum could reach at 0.808 6 g/dL after 7 days culture.