Screening and Molecular Identification of Strain that Produced Inulinase in Qinghai

The 46 strains that produced inulase were screened from rhizosphere soil where Jerusalem artichoke was planted in Qinghai.One strain with high inulinase productivity was obtained through further screening and the enzyme activity was6.67 U/ml.This inulinase was exonuclease.Through determination and analysis of the r DNA-ITS sequence,and analysis of morphology,the fungus was identified as Actinomucor elegans.

Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.

Screening and Identification of Strains Converting Trans-anethole to Anisic Acid

[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to the traditional microbial culture method, with trans-anethole as the sole carbon source, through enrichment culture and separation and purification, preliminary screening by thin layer chromatography and re-screening by high-performance liquid chromatography, strains that degraded trans-anethole to produce anisic acid were obtained, and 16 S rDNA sequencing and phylogenetic tree construction were performed for genetic analysis. [Results] Eleven strains that degraded trans-anethole to produce anisic acid were obtained, among which strain NT2 that produced anisic acid with a relatively high efficiency was initially identified as Pseudomonas sp. The strain’s trans-anethole degradation rate was 45.41%, and the molar production rate and cumulative concentration of anisic acid were 21.80% and 1.96 g/L, respectively. [Conclusions] Strain NT2 has a strong ability to degrade trans-anethole to produce anisic acid, and can enrich strain resources for degradation of trans-anethole to anisic acid through microbial conversion.

Study on Rational Breeding of High-Yield Avermectin Industrial Strain

[Objective] Strain Biok Av-023 used as the control was employed on screening of high-avermectin yield mutants by rational screening.[Method] With Biok Av-023 as the original strain,the positive mutation strain was firstly screened by routine UV mutagenesis,and then the high-yield avermectin producing strain was selected by the breeding way inferred by L-Ile induction.[Result] UV mutation and L-Ile directional screening had showed that the best L-Ile screening concentration was 0.5%,and the high-yield mutation strain AV60s-32 after re-screening reached the highest titer of 4520 IU/ml,which increased by 23.4% compared with the original strain.[Conclusion] The production of avermectin can be effectively enhanced by the combined way of UV mutation and L-Ile rational breeding.

Screening of strains with potential hypoglycemic effect and its application in fermented garlic production

Microbial fermentation could produce many active substances in green and pollution-free ways.In recent years,studies on the hypoglycemic ability of microorganisms had become a trending topic in the prevention and treatment of diabetes.Garlic is a food containing a variety of biologically active substances and physiological functions,but it is not accepted by the general public because of its strong pungent smell.In our study,the microorganisms with potential hypoglycemic effect were screened from strains resistant to garlic juice.As a result,41 strains of Bacillus,157 strains of lactic acid bacteria,and 23 strains of yeast with tolerance of garlic juice were screened from the selected 568 strains.After primary screening ofα-amylase inhibitor,it was found that 15 Bacillus and 9 lactic acid bacteria had highα-amylase inhibitory activity.Besides,afterα-glucosidase inhibitor re-screening,Pediococcus acidilactici Z1 with highα-amylase inhibitory activity andα-glucosidase inhibitory activity was screened out.The results of fermented garlic showed that the inhibition rate ofα-amylase andα-glucosidase of garlic from different origins were significantly increased from 59.09 to 63.99%(p<0.01)and from 52.71 to 71.93%(p<0.01)after Z1 fermentation,respectively.The improvement rates ofα-amylase andα-glucosidase were 107.69 to 287.32%,and 197.74 to 239.86%,respectively.In a word,this study provides a theoretical and experimental basis for the development of new functional garlic products.

Reducing Yield of Fusel Alcohols by Saccharomyces cerevisiae of Compound Mutagenesis Through UV-MPMS Method

Excessive fusel alcohol contents will cause the beer to produce off-flavors and cause dizziness and headaches.Reducing the contents of fusel alcohols in beer is very important to people's health.The excessive fusel alcohol contents in beer is a common problem in the industry.How to control the contents of fusel alcohols in a reasonable range is of great significance for improving beer quality.After one round of ultraviolet(UV)and one round of multifunctional plasma mutagenesis system(MPMS)mutagenesis,the yeast strains with lower fusel oil yield and more stablility could be screened.According to the relationship between the fusel alcohol Harris metabolic pathway of brewer's yeast and lactic acid metabolism,excellent strains were obtained by triple screening with lactic acid medium,calcium carbonate medium and 2,3,5-triphenyl tetrazolium chloride upper medium.The content of fusel alcohol in the finished beer fermentation test of screened strain Z43 was 52.1±0.142 mg•L^(-1),which was 43%lower than that of the starting strain,and other fermentation properties remained unchanged.After eight passages,it was verified that the strain was stable and heritable.These results showed that strain Z43 presented promising characteristics for use in the production of beer with a potentially low contents of fusel alcohols.

Isolation and Identification of a Nitrite-oxidizing Bacterium from Hepu County

In order to select the strain that can degrade nitrite, the screening plate with nitrite was used as the sole nitrogen source to screen the strain with ability to degrade nitrite. A strain with nitrite degrading capacity was isolated from the sludge of a shrimp-farming pond in Hepu City, Guangxi Zhuang Autonomous Region. The isolated strain was identified based on colonial morphology, physiological and biochemical characteristics, and 16S rRNA sequence. Results showed that the strain could grow well on the culture medium containing 2.3 g/L nitrite. According to the morphological characteristics, nitrogen source requirements and evolutionary tree of the 16S rRNA sequence, the isolated strain was identified as Acinetobacter radioresistens, which was named HPAR132 strain. This study laid the foundation for further investigation of nitrite-oxidizing bacterium HPAR132.

Isolation and Identification of a Cellulose-degrading Bac- terium from Paddy Soils in Chengdu City

In this study, a cellulose-degrading bacterium was isolated from paddy soils in Chengdu City. After 2 d of culture, the average diameter of hydrolytic circles on CMC-Congo red medium was 26 -30 mm. Single colonies on LB plates were white and wrinkled. The isolated strain was identified as a Gram-negative bacterium by Gram staining, which could produce short red-like spores. Colony PCR was performed using the bacterial 16S rDNA universal primers. A 1 429 kb DNA fragment was amplified. Based on sequence homology analysis and comprehensive analysis, the isolated strain was identified as Bacillus velezensi, which was named CDBV62 according to the origin.

Effects of strain,nutrients concentration and inoculum size on microalgae culture for bioenergy from post hydrothermal liquefaction wastewater

Cultivating microalgae in post hydrothermal liquefaction wastewater(PHWW)offers many benefits,including nutrients recovery and reuse,wastewater purification and biomass production.However,the high nutrients concentration and toxic substances in PHWW undermine the efficiency of biomass production and nutrient recovery.This study aimed to investigate the effects of the microalgae strains,initial nutrients concentrations and inoculum sizes on biomass production and nutrient recovery using PHWW as the cultivation medium.Results indicated that both biomass production and nutrients recovery were successfully improved by using the screened microalgae strain at the desirable initial nutrient concentration with the suggested algae inoculum size.Chlorella vulgaris 1067 probably demonstrated the strongest tolerance ability among the five microalgae strains screened,and performed well in the diluted PHWW,of which initial TN concentration was approximately 500 mg/L.The desirable inoculum size was determined to be 0.103-0.135 g/L.The biomass daily productivity was increased by 15.67-fold(reached 0.13 g/(L·d)).With the above optimal conditions,high biomass production and nutrient recovery from the PHWW to produce microalgae biomass for bioenergy production were achieved.