Dataset Information

Isolation of Marine Bacillus sp. with Antagonistic and Organic-Substances-Degrading Activities and Its Potential Application as a Fish Probiotic.

ABSTRACT: We report on the isolation and characterization of an acid- and bile-tolerant bacterial strain, Bacillus sp. YB1701 with antibacterial and quorum-quenching activity. Strain YB1701 was isolated from coastal sediment samples and characterized by biochemical tests and 16S rRNA sequencing. In vitro study indicated that strain YB1701 can survive at pH 2.0 for up to 3 h and tolerate bile up to 2.0% concentration even after 12 h of exposure. Strain YB1701 showed antimicrobial activity against fish pathogens Aeromonas hydrophila and Vibrio parahemolyticus using an agar well diffusion assay. The trial test showed dietary supplementation of YB1701 significantly improved the resistance of Carassius auratus gibelio against A. hydrophila challenge. The safety assessment revealed that the isolate Bacillus sp. YB1701 was not cytotoxic to Carassius auratus gibelio or mice and did not exhibit hemolytic activity on rabbit blood agar plate. Disc-diffusion assays using a panel of antibiotics listed by the European Food Safety Authority (EFSA) showed that YB1701 was susceptible to selected antibiotics. Under laboratory conditions, the degradation rate of organic waste (predominately fish excrement) for 14 days by YB1701 was 79.69%. Results from the present study suggest that strain YB1701 is a potential probiotic strain and can be used in aquaculture for degrading organic waste and improving disease resistance of fish against bacterial infection. Further study is needed to assess the utility of strain YB1701 on a commercial scale.

SUBMITTER: Zhou S

PROVIDER: S-EPMC6025278 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Isolation of Marine <i>Bacillus</i> sp. with Antagonistic and Organic-Substances-Degrading Activities and Its Potential Application as a Fish Probiotic.

Zhou Shuxin S Xia Yu Y Zhu Chongmiao C Chu Weihua W

Marine drugs 20180605 6

We report on the isolation and characterization of an acid- and bile-tolerant bacterial strain, <i>Bacillus</i> sp. YB1701 with antibacterial and quorum-quenching activity. Strain YB1701 was isolated from coastal sediment samples and characterized by biochemical tests and 16S rRNA sequencing. In vitro study indicated that strain YB1701 can survive at pH 2.0 for up to 3 h and tolerate bile up to 2.0% concentration even after 12 h of exposure. Strain YB1701 showed antimicrobial activity against fi ...[more]

PMID: 29874792

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Project description:BackgroundFeathers are the most abundant agricultural waste produced by poultry farms. The accumulation of a large number of feathers not only seriously pollutes the environment but also causes the waste of protein resources. The degradation of feather waste by keratinase-producing strains is currently a promising method. Therefore, screening high-producing keratinase strains from marine environment and studying the fermentation conditions, enzymatic properties and feather degradation mechanism are crucial for efficient degradation of feathers.ResultsA novel efficient feather-degrading bacteria, Gxun-17, isolated from the soil sample of a marine duck farm of Beibu Gulf in Guangxi, China, was identified as Bacillus tropicus. The optimum fermentation conditions were obtained by single factor and orthogonal tests as follows: feather concentration of 15 g/L, maltose concentration of 10.0 g/L, MgSO4 concentration of 0.1 g/L, initial pH of 7.0 and temperature of 32.5 °C. The strain completely degraded the feathers within 48 h, and the highest keratinase activity was 112.57 U/mL, which was 3.18-fold that obtained with the basic medium (35.37 U/mL). Detecting the keratinase activity and the content of sulphur-containing compounds in the fermentation products showed that the degradation of feathers by the strain might be a synergistic effect of the enzyme and sulphite. The keratinase showed optimal enzyme activity at pH 7.0 and temperature of 60 °C. The keratinase had the best performance on the casein substrate. When casein was used as the substrate, the Km and Vmax values were 15.24 mg/mL and 0.01 mg/(mL·min), respectively. Mg2+, Ca2+, K+, Co2+, Al3+, phenylmethylsulphonyl fluoride and isopropanol inhibited keratinase activity, which indicated that it was a serine keratinase. Conversely, the keratinase activity strongly increased with the addition of Mn2+ and β-mercaptoethanol.ConclusionsA novel feather-degrading B. tropicus Gxun-17 was obtained from marine environment. The strain adapted the extreme conditions such as low temperature, high salt and high pressure. Thus, the keratinase had high activity, wide range of temperature and pH, salt tolerance and other characteristics, which had potential application value.

Dataset Information

Isolation of Marine Bacillus sp. with Antagonistic and Organic-Substances-Degrading Activities and Its Potential Application as a Fish Probiotic.

Publications

Isolation of Marine <i>Bacillus</i> sp. with Antagonistic and Organic-Substances-Degrading Activities and Its Potential Application as a Fish Probiotic.

Similar Datasets

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