Abstract:Microbial fermentation was the mainly method to product L-leucine presently. Improving the strain production of L-leucine by breeding high-yielding strains is helpful for shortening of the gap with foreign production and improving our international competitiveness with foreign. This paper stated the methods of L-leucine production,regulation of biosynthesis enzymes,transporter and leucine responsive protein,and the research evolution of the breeding of L-leucine hyper-producter were summarized at home and abroad.

Abstract:Following the functional foods were constantly pursued,the probiotic microorganisms in traditional food are continuously developed and utilized. L. fermentum,as dominant lactic acid bacteria in traditional fermented food,has the characteristics of security and genetic stability. This paper emphatically describes the distribution of L. fermentum in traditional foods,and the probiotic characteristics and mechanism of L. fermentum on tolerance to the adverse environment in animal intestine,degradating of cholesterol,inhibiting spoilage and pathogenic bacteria,improving the body's immunity,and so on. The safety aspect of L. fermentum is research as well. These what has done above will offer theory basis about L. fermentum as high quality probiotic food starter culture.

Abstract:Wheat straw was used as basic substrate and supporter for laccase production under solid-state fermentation(SSF) in this essay and optimized its best suitable cultural conditions for laccase production including carbon and nitrogen sources,initial moisture and physical size of wheat straw. Meanwhile,the reduced sugar generated during the SSF was measured and the function of the white-rot fungi in wheat straw degradation. Furthermore,we compared the consistence of wheat straw before and after SSF containing nitrogen sources.

Abstract:The addition of leucine was proved to improve the tolerance of Lactococcus lactis NZ9000 to acid stress. When cultivated with leucine under acid stress(pH 5.0),the biomass of L. lactis NZ9000(Leu+) increased 1.24 fold,compared to L. lactis NZ9000(Leu-) (without leucine addition). After challenged at pH 4.0 for 5 h,the survival rate of L. lactis NZ9000(Leu+) increased 28.5 fold,compared to L. lactis NZ9000(Leu-). Further measurements indicated that the addition of leucine could improve the concentration of intracellular NH4+,help to maintain the intracellular pH(pHin) at a relatively high level and protect the activity of lactate dehydrogenase(LDH). Therefore,the addition of leucine could enhance the acid tolerance of L. lactis.

Abstract:Lactobacillus paracasei LN-1 with salt tolerance property was isolated from traditional fermented food,suancai,which was made in the northeast of China. In order to understand the mechanism involved,proteomics analysis was undertaken to reveal the response of the strain during growth in medium with or without NaCl using two-dimensional electrophoresis(2-DE). Out of 20 protein spots that showed differential changes in expression,seven spots were identified by matrix assisted laser desorption and ionization time-of-flight mass spectrometry(MALDI-TOF/MS). Further analysis showed that chaperone protein(GroEL and DnaK) and fatty acid biosynthesis enemy(Fab G) possibly play important role in Lactobacillus paracasei LN-1 to resist to salt stress.

Abstract:Five bacterial cellulose(BC) producing strains were isolated from solid-state fermentation cultures of traditional Chinese vinegar,and identified as Gluconacetobacter intermedius based on their physiological and biochemical characteristics as well as 16S rDNA sequence analysis. Strain 1-17 could produce more BC then the others. Furthermore,surface features and chemical structure of BC were analyzed by scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) spectroscopy,respectively. Effects of temperature,time,carbon sources and initial pH on BC production were tested. The optimal temperature for strain 1-17 was 35 ℃,and the fermentation time was 7 d. Glucose and glycerol were the optimal carbon sources,and the optimal initial pH was 6.0. Both lactate and calcium could promote the synthesis of BC. The yield of BC was improved from (3.90±0.08) g/L to (7.90±0.19) g/L under the optimal conditions.

Abstract:Human serum albumin(HSA),the most abundant protein in plasma,with functions of regulating blood protein,fatty acids,hormones,drugs,and representing the main determinant of plasma oncotic pressure,providing a depot and carrier for many endogenous and exogenous compounds. The engineering pichia pastorios GSll5/pPIC9K-rHSA was fermented by 50 L fermentor. Highly purified rHSA was separated from fermentation supernatant by ultra filter,Blue sepharose affinity chromatography,Phenyl sepharose hydrophobic chromatography and SP sepharose ion exchange chromatography purification．Eventually the purity of rHSA can reach more than 99.9%. Through screening crystallization conditions of rHSA,five conditions with precipitant of PEG 1500,PEG 3350,PEG 6000,MPEG 2000 and MPEG 5000 were obtained. The crystallization condition was hydrophobic and without strong reductant like DTT. Crystals of rHSA and pHSA with precipitant of MPEG 2000 were best for X ray diffraction,respectively the resolution were 3.4 ?魡 and 3.1 ?魡. Crystal structure of rHSA and pHSA were the same as a whole that obtained through molecular displacement method. The results provided reliable basis and foundation for the clinical application of rHSA and crystal structure study of HSA fusion proteins.

Abstract:10 samples of traditional fermented soybean paste were collected from northeast of china. Comprehensive evaluation of free amino acid content were carried out by using PCA and SPSS. The main results showed that different samples had different comprehensive evaluation index of free amino acid content,the free amino acids of sample QQHE1 was the highest,followed by TL1 sample,the lowest was sample YK1.

Abstract:In this manuscript,the endophyte of Paris polyphylla Smith var．yunnanensis(Franch) was isolated and identified. 40 and 44 endophytic bacteria were isolated from the root of cultivated or wild Paris polyphylla Smith var．yunnanensis in Wenshan,Yunnan province. They were then identified and categorized as 6 and 8 genera by 16S rRNA gene sequenceing. Bacillus and Enterobacter were dominant genera in cultivated of Paris polyphylla Smith var．yunnanensis because they accounted for 35% and 27.5% respectively in the identified bacteria;Bacillus and Klebsiella were dominant genera in wild Paris polyphylla Smith var．yunnanensis and accounted for 36.4% and 20.4% respectively. The results reflected the difference and biodiversity of endophytic bacteria between cultivated Paris polyphylla Smith var．yunnanensis and wild ones. This study provides theoretical and experimental basis for subsequent development of Paris polyphylla Smith var．yunnanensis.

Abstract:A ultra performace liquid chromatography(UPLC) method was applied to determinating the contents of betulin,ergosterol,lanosterol,cholesterol,stigmasterol and sitosterol in the submerged-cultured mycelia of Inonotus obliquus. The procedure was carried out on a shim-pack XR-ODSⅢ column(150 mm×2 mm,2.2 μm),using acetonitrile(100%) as mobile phase with a flow rate of 0.8 mL/min. The detecting wavelength was 202 nm and the column temperature was 30 ℃. This method had good reproducibility and satisfactory recoveries The relative standard deviations of this method were less than 0.10%~0.33%(n=5) and 0.07%~1.66%(n=5) for intraday and inter-day assays,respectively. A good linear correlation was obtained in a range of 0.3~1.6 μg. The recoveries of betulin,ergosterol,lanosterol,cholesterol,stigmasterol,and sitosterol were 97.05%,98.74%,95.65%,101.45%,96.62%和96.14%,respectively. This method could be applied to evaluate real samples,and it was rapid,accurate and suitable for the quantitative determination of the six steroids in the submerged-cultured mycelia of Inonotus obliquus.

Abstract:In order to detect bacteria from the complex ecological environment for liquor-making,we developed a novel and efficient assay for identification and quantification of bacteria.We selected Bacillus to be experimental bacterium.Three oligonucleotide probes targeted 16S rRNA of Bacillus were respectively designed.Then the assay based on microplate sandwich hybridization assay with the aid of S1 nuclease treatment(S1-MSH)was developed. Meanwhile,several key operating conditions were respectively optimized.The results showed that the probes targeted Bacillus showed high accuracy for distinguishing homologous species such as Staphylococcus,Acetobacter and Pseudomonas. Besides,the assay could distinguish homologous species with the exclusion of even only one base difference when the reaction temperature of nuclease S1 was 42 ℃.When the concentrations of capture probe and signal probe were 5 nmol/L,the hybridization time were respectively 60 min and 15 min,and hybridization temperatures were 50 ℃,the color intensity was positively linear related to the cellular number,and the detection limit was low to 1.33×102 cells/mL.Therefore,this assay method could be applied for identifying and monitoring Bacillus during liquor fermentation,and the research offers an efficient method for rapid identification and quantification of microbiology in the liquor fermentation process.

Abstract:A neutral cellulase-producting bacterium was screened from soil,and this strain was identified as Bacillus through 16S rDNA sequence analysis. With it as a starting strain,we constructed a response surface methodology(RSM) model by single factor and factorial test,ascent experiment and central composite experiments. By this RSM model,we obtained the optimal medium containing 1.97% maltose,2.03% yeast extract-tryptone(1∶4,m/m) mixed nitrogen. The enzyme activity increased from 130.40 U/mL to 194.23 U/mL under the optimal conditions.

Abstract:The salted egg white and starch as the main raw material in the experiment,this paper investigated the effect of the added amount of glutinous rice flour and corn starch,the surimi added amount,the maltodextrin added amount,water content,microwave power and jet frequency on expansion of recombinant plasmids,the expansion ratio and breaking force as index.The experimental results show that the ratio of glutinous rice flour and corn starch is 1:1,the surimi added 50%,the maltodextrin added amount 5%,water content 46%,microwave power 48W/g and spouted frequency 4 /min ,with the optimum composition,the quality of the puffed productd and the expansion ration and crispness are better.

Abstract:Oxidative injury was induced by high glucose. Cell viability,production of ROS,the activity of superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px),malondialdehyde(MDA) content,insulin secretion and related genes level were measured to investigate the effect of different concentration of GABA(10、50、100 μmol/L) on RIN-m5f cells in high glucose-induced oxidative injury model. The results demonstrated that GABA improved the cell viability,reduced ROS ptoduction,significant enhanced the activity of SOD and GSH-Px,lowered the MDA content,ptomoted insulin secretion,increased the mRNA level of Nrf2 and Bcl-2,and decrease the mRNA level of GSK-3β and Bax. It follows that GABA possesses the anti-apoptosis and anti-oxidative protective effect on RIN-m5f,and this ptotection may be achieved by inhibit GSK-3β and then inhibit Bax,and activate several key factors such as Nrf2 and Bcl-2.

Abstract:5'-cytidine acid and choline calcium phosphate as the substrates were converted into CDP-C by Issatchenkiaorientalis.The optimal conversion condition was as follows:CMP17.5 g/L,choline calcium phosphate 12.5 g/L,potassium hydrogen phosphate 12.5 g/L,seven hydrated magnesium sulfate 3.0 g/L,manganese sulfate 0.6 g/L,glucose 50 g/L,toluene 30 mL/L,Yeast mud 375 g/L,and the pH of convert liquid 8,the output of CDP-C can reach more than 10 g/L,up to 11.592 g/L. The conversion solution was decellularized,deproteinized and the CDP-C was obtained by eluting 717 ion exchange resin with 0.05 M NaCl,whose purity was more than 98%.

Abstract:The molecular weight of hyaluronic acid significantly affected its physicochemical properties and application effects. Effects of different culture conditions on the molecular weight of hyaluronic acid synthesized by Streptococcus equisimilis was compared,the results of which indicated that glucose with high concentration benefited the synthesis of long-chain hyaluronic acid. The concentration of glucose had significantly effect on the molecular weight of hyaluronic acid. With the initial concentration of glucose enhancing from 20 g/L to 80 g/L,the molecular weight of hyaluronic acid was increased to 2.02×106 from 1.24×106,i.e.,increased by 62.9%. Feeding mode of glucose significantly affected the molecular weight of hyaluronic acid. The molecular weight of hyaluronic acid was respectively 1.53×106 and 1.42×106 through interval and continuous feeding modes of glucose,which was decreased by 19.9% and 25.7% by comparing with batch culture. Low temperature was beneficial to the synthesis of high-molecular-weight hyaluronic acid. Under the culture condition of 33 ℃,the molecular weight of hyaluronic acid could reach to 2.54×106 at the maximum. pH also significantly affected the molecular weight of hyaluronic acid. When pH was 8,the molecular weight of hyaluronic acid reached to the highest 2.38×106. Dissolved oxygen with higher level benefited the sythesis of high-molecular weight hyaluronic acid,within the concentration range of 0~45% of dissolved oxygen,the molecular weight was increased to 2.43×106 from 1.16×106 with the increasing concentration of dissovled oxygen,increased by 109.4%.

Abstract:In this work,surface response methodology (RSM) was used for simultaneous analysis of levels of superfine grinding protein powder,Nacl,cassava starch,sodium alginate and wheat gluten on quality factors of high quality noodle such as sensory acceptability,hardness,springiness,chewiness,swelling degree,dissolution rate and maximal stress force. The results show that the high quality noodle can be obtained by the additions of superfine grinding protein powder 2.84 g/dL,cassava starch 11.63 g/dL,NaCl 1.87 g/dL,sodium alginate 0.3 g/dL and wheat gluten 2 g/dL.