Abstract:Pesticides，veterinary drugs，illegal additives and poisonous and harmful chemical pollutants in foods and environment have aroused more and more concerns. These residues are mostly assayed by competitive immunoassay modes due to their small molecular weight and single epitope. Since the sensitivity，stability，and liner range of competitive immunoassays are not as good as those in non-competitive sandwich immunoassays，methodological improvements could made non-competitive immunoassays suitable. Herein this review summarized their principles，elements and applications of non-competitive immunoassays for the detection of small molecules during last decades.

Abstract:Pyrroloquinoline quinone（PQQ） is a new coenzyme that has broad application prospect. Previous methods used for measuring PQQ in fermentation broth are defective and low-efficient. In this study，D-glucose dehydrogenase（PQQGDH） from Escherichia coli K-12 was expressed in E. coli BL21 and then purified by the nickel-affinity chromatography column. For the high-throughput measurement of PQQ the optimal reaction system was found by orthogonal experiment to contain 30 μL PQQGDH，2 μL PQQ sample and 1.2 mL chromogenic reagent. The method was linear within a wide range and had high precision and good reproducibility. Compared with traditional methods，the high-throughput measurement of PQQ using purified PQQGDH，96-well plate and microplate reader are herein more accurate and efficient.

Abstract:To enhance production and activity of G. lucidum exopolysaccharides（EPS），a mixed carbon source containing glucose，galactose and mannose was applied and effects of mixed carbon sources on cell growth，EPS composition and antitumor activity were studied. Results showed that dry cell weight and EPS production were slightly affected by the ratio and type of monosaccharides. Anti-tumor activity analysis of G. lucidum EPS indicated that the raise of EPS concentration increased its biological activity. The inhibition reached up to 50%~60% with the ratio of glucose to galactose 1∶1 as carbon source，75%~85% with the ratio of glucose to galactose 1∶2，60%~65% with the ratio of glucose to mannose 1∶1，80%~85% with the ratio of glucose to mannose 1∶2 and 80%~85% with the same concentrations for three monosaccharides. The high ratio of galactose or mannose in culture medium was beneficial to the anti-tumor activity of EPS against the growth of A431and MDA-MB-231 cells.

Abstract:With the probe of quantum dots coupled with microcystin antibody（QDs-Ab），the content of microcystin was determined by measuring cadmium ions released from QDs based on square wave stripping voltammetry after indirect competitive reaction. The electrochemical response was optimized with respect to pH，buffer concentration，deposition potential，deposition time and so on. Results showed that the sensitive stripping peak potential of cadmium ions was about -0.768 V. Under the optimal conditions，the peak current was linear with the logarithm of microcystin concentration in the range of 0.1~8 μg/L and the equation of regression was y=-196.66x+242.15（R2=0.994 8） with a detection limit of 0.08×10-9. The recovery of standard addition experiment was in the range of 91%~108.6% with the relative standard deviation of 2.97%~6.98%.

Abstract:In order to understand the influence of ice-storage and superchilling on the quality of Leiocassis longirostris fillets and develop appropriate storage technology，changes in physicochemical，microorganism and texture indexes during storage were investigated. Results indicated that pH value didn't change significantly for two storage methods，whereas the total volatile basic nitrogen（TVB-N） and the microbial population increased gradually with extended storage and superchilling more effectively delayed the changes than ice storage. Water holding capacity（WHC），hardness and springness all declined under both storage conditions and myofiber gaps gradually enlarged in the meantime. Ice storage more effectively slowed down these changes of physical properties. The shelf life of iced and suprechilled channel catfish fillets was 13 days and 19 days，respectively，and as a whole superchilling storage could more effectively inhibit biochemical deterioration than ice storage.

Abstract:Gammaglutamyltranspeptidase gene from Bacillus subtilis 168 was cloned and overexpressed with pMA5 vector in Bacillus subtilis 168 for overproduction of GGT. GGT was secreted in the extracellular space. The overexpressed enzyme was 3568 fold higher in activity than that from the parent strain and exhibited a specific transpeptidase activity of 49.8 U/mg. The molecular mass of two sub-units was estimated to be 42 000 and 22 000 respectively，by SDS-PAGE. The overexpressed GGT was a very versatile enzyme in alkaline pH. Its optimal temperature was 50 ℃ showing a moderately high thermostability. The effect of ions on purified GGT was also examined. Results showed that NH4+ had the highest activation effect on GGT（>45%），other ions such as Ca2+、K+、Mg2+、Li+ and La3+ had a significant activation effect on the enzyme，whereas Cu2+ and Zn4+ recorded the highest deactivation on GGT activity.

Abstract:To analyze the effect of transcription factor CgAsg1p on the robustness of Candida glabrata，the mutant strain Cgasg1?驻 was constructed and the cell growth，gene transcriptional level and the ability of resisting various stresses were investigated. Compared to the wild-type strain C. glabrata ATCC 2001，the mutant strain Cgasg1?驻 lost the ability of surviving in the medium at pH 2.0. CgAsg1p changed the transcription level of several response genes，influencing stress regulation，redox process，transmembrane events，DNA replication，recombination and repair，etc. Besides，the mutant strain Cgasg1?驻 lost the ability of resisting oxidative stress and hyperosmotic stress. These results indicated that CgAsg1p is an essential transcription factor in C. glabrata for various stress responses.

Abstract:Extraction of lard with aqueous enzymatic method was studied. Four proteases，Alcalase 2.4 L，Neutrase 1.5 MG，Flavourzyme 1 000 L and Protamex were evaluated for their efficiency in oil release，and Alcalase 2.4L was found to the most effective for oil-extraction. The optimal hydrolysis parameters for Alcalase 2.4L were hydrolysis time 2.0 h，temperature 55 ℃，pH 8.0，ratio of material to water 1 g∶1 mL and enzyme amount 1%（E/S），which resulted in an oil extraction yield of 96.82%. Lard obtained by the enzymatic extraction was superior to those by traditional methods according to physicochemical properties.

Abstract:The chlorogenic acid was a natural bioactive ingredient which was usually hindered in the dense structure of plant fibers and difficult to be extracted. An enzymatic cell wall-breaking process was thus developed using the combination of cellulase and ligninase to reduce transfer resistance during extraction and to improve the extraction efficiency of chlorogenic acid from Lonicera japonica leaves. The antioxidant activity in vitro of chlorogenic acid was evaluated by DPPH free radical scavenging method and ferricyanide reduction analysis. The product of enzymatic hydrolysis by the dual-enzyme complex was characterized by SEM. The complex was confirmed to effectively destruct the plant fiber structure and help to form the internal loose structure. The effect of various metal ions on the enzyme activity were weakened in the order of Mg2+，Na+，Ca2+，K+，and Cu2+. The optimized extraction condition was determined using 3∶2 of cellulase to ligninase ratio （U/U） with 50 U/g of enzymes/substrate and Mg2+ at 45 ℃ and pH 4.0 for 11 h. Under the optimal condition，the extraction rate of chlorogenic acid could reach as high as 94.68%，which was 19.60% higher than that of ultrasound-assisted ethanol extraction. The anti-oxidative of reductive activities of chlorogenic acid were improved. This study provides a theoretical foundation to the comprehensive utilization of Lonicera japonica leaves and industrialization of chlorogenic acid.

Abstract:Based on monofactorial experiments，Plackett-Burman（PB） design and response surface methodology（RSM） were applied to optimize 8 medium components for the production of pigments by marine bacteria strain Planococcus rifietoensis. Results showed that optimal carbon and nitrogen sources of the medium were glucose and peptone，respectively，and glucose，yeast extract and MgSO4·7H2O had major effects on the production of pigments. The optimal culture medium was comprised of glucose 9.78 g/L，peptone 8.00 g/L，yeast extract 2.05 g/L，MgSO4·7H2O 8.17 g/L，Na2HPO4 0.1 g/L，FeSO4·7H2O 0.005 g/L，NaCl 10 g/L and CaCl2 0.1 g/L. The incubation time was 54 hours. Under these conditions，the optical density（OD） of pigments reached to 0.984，which was 245% higher than that before optimization.

Abstract:Gama（γ）-aminobutyric acid（GABA），which has a variety of physiological functions，is widely used in food，pharmaceutical and other industries. Two L-glutamate decarboxylase（GAD） genes（gadB1 and gadB2） were co-expressed previously in an L-glutamate producing strain Corynebacterium glutamicum ATCC13032，making the own accumulated L-glutamate be effectively transformed into GABA. To further enhance GABA production，the pknG gene encoding serine/threonine protein kinase PknG was deleted to improve the supply of GABA precursor L-glutamate. Then the co-expression plasmid pJYW-4-gadB1-gadB2 was transformed into pknG deletion strain and ATCC13032，generating the recombinant C. glutamicum strains SNW203 and SNW200. After the strains were fermented in fermenters，the production of both L-glutamate and GABA in SNW203 increased greatly when compared with SNW200. At 72 h of fermentation，GABA production in SNW203 increased to （30.2±0.3） g/L，55.4% higher than that in SNW200 and the total concentration of L-glutamate and GABA reached up to 0.3 mol/L，36.4% higher than that in SNW200. This result indicates that the deletion of pknG improves the biosynthesis of L-glutamate and GABA in recombinant C. glutamicum.

Abstract:This study aimed to degrade the pectin in the tobacco stem end by pectinase from Penicillium and improve its usability as raw material for the reconstituted tobacco. Optimal degradation parameters obtained by the orthogonal method were enzyme dosage 0.6 g，solid/liquid ratio 1∶3，reaction temperature 50 ℃ and time 2 h，which resulted in a maximum degradation rate of 38.51%. Thermogravimetric analysis showed that the residual weight of tobacco stem end was decreased from 24.46% to 9.84% after enzymolysis，indicating that its burning capacity was improved. Pyrolysis-GC/MS analysis found that the content of acetic acid in the smoke was decreased and pyrrole was increased，which would benefit the smoke taste. This study provided a new method to improve the quality of reconstituted tobacco.

Abstract:This study aimed to fabricate a novel Ag nano-particles（AgNPs） loaded biologic dressing based on silk fibroin（SF） and sodium alginate（SA）. AgNPs were first synthesized in the stabilizer，SF solution，under UV irradiation，and after the addition of SA，were then treated by CaCl2/ethanol /water（molar ratio，1∶71∶77） for 3 h. After rinsing and freeze-drying，AgNPs loaded SF/SA composite sponge（AgNPs-SF/SA） was obtained. Transmission electron microscopy observation（TEM） showed that AgNPs were evenly distributed in the SF solution with a mean diameter of 5.03 nm. Scanning electron microscopy（SEM） images showed that compared with pure SF sponge，AgNPs-SF/SA had a linked porous structure. Addition of SA improved the water absorption and retention ability of the sponge and the synergistic effect of SF and SA increased the water vapor transmission rate. K-B disk diffusion and bacterial solution culture methods indicated that AgNPs-SF/SA possessed a higher and more continuous anti-bacterial potential than the positive control，AQUACEL?誖 Ag，against P. aeruginosa and S. aureus. In conclusion，the excellent physical and anti-bacterial properties demonstrated that AgNPs-SF/SA could be a novel anti-bacterial biologic dressing for prevention and treatment of wound infection.

Abstract:A series of physical and chemical indexes of dried scallop were studied to investigate the effect of relative humidity（RH） on the quality of dried scallops during storage within 90 days at 4 ℃，including water activity（aw），pH，color change，total volatile basic nitrogen（TVB-N），peroxide value （POV） ，thiobarbituric acid reactive substances（TBARS） and microstructure of the product. The total TVB-N value，POV value，TBARS value of dried scallop stored in a lower relative humidity（RH23% and RH43%） showed insignificant changes during storage，while significantly increased when stored at higher relative humidity（RH65% and RH84%）. A lower relative humidity was thus recommended for the storage of dried scallop.

Abstract:Based on the comparative analysis of microbiological criteria for ready-to-eat foods in Codex Alimentarius Commission，the European Union，Australia，New Zealand，England，Canada，America，Korea，Hong Kong and Macau，the article provided recommendations for the elaboration of Chinese national microbiological standards for ready-to-eat foods.