Screening of Antimicrobial Marine Microorganisms and Purifying of Its Bioactive Substances
A bacterium HS-A38 with antimicrobial activities was isolated from the intestine of wild sea cucumbers in Dalian sea area. Based on the analysis of morphological, physiological, and 16S rDNA sequence, the strain HS-A38 was identified as Bacillus subtilis.
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Screening of Antimicrobial Marine Microorganisms and Purifying of Its Bioactive Substances Zhiwen Liu, Qiankun Ruan, Sirigulen Qian and Lina Cong
Abstract A bacterium HS-A38 with antimicrobial activities was isolated from the intestine of wild sea cucumbers in Dalian sea area. Based on the analysis of morphological, physiological, and 16S rDNA sequence, the strain HS-A38 was identified as Bacillus subtilis. Two bioactive substances (1 and 2) were purified from the fermented broth of the Bacillus subtilis HS-A38 using the methods of fractional sedimentation with ammonium sulfate, CM-52 ion-exchange chromatography and Sephadex G-75 column. The SDS-PAGE analysis indicated that the relative molecular weight of these bioactive substances were 41 kDa and 28 kDa, respectively. The antibacterial spectra showed that substance 1 could only inhibit Gram-positive bacteria, whereas substance 2 could significantly inhibit both the Gram-positive and negative bacteria. Keywords Antibacterial activities Bioactive substance Purification
Antimicrobial marine microorganisms
120.1 Introduction Bioactive substances are believed to play a key role in microbial interactions by mediating antagonistic activity and intercellular communication [1]. In addition, many microbial natural products have biotechnological potential as antibiotics,
Zhiwen Liu and Qiankun Ruan contributed equally to this work. Z. Liu Q. Ruan S. Qian L. Cong (&) College of Bio & Food Technology, Dalian Polytechnic University, Dalian 116034, Liaoning, People’s Republic of China e-mail: [email protected]
T.-C. Zhang et al. (eds.), Proceedings of the 2012 International Conference on Applied Biotechnology (ICAB 2012), Lecture Notes in Electrical Engineering 250, DOI: 10.1007/978-3-642-37922-2_120, Ó Springer-Verlag Berlin Heidelberg 2014
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biosurfactants, antifungal, or anticancer agents [2]. Sequences of microbial genomes revealed that only a small fraction of the natural product diversity is known, which highlighted the potential for finding novel bioactive compounds in environmental microorganisms [3]. The need for novel antimicrobials to combat increasing antibiotic resistances in pathogenic bacteria has stimulated the exploration of other than the traditional sources, such asterrestrial actinomycetes or fungi [4]. The marine environment harbors bacteria with antagonistic traits [5, 6], and marine microorganisms are a potential source of novel antimicrobials [7]. Antagonistic marine bacteria have been isolated from surface and deep waters [8, 9], but the majority originated from biotic surfaces such as sponges [10], zooplankton and macroalgae [11], corals [12], and bryozoans [13]. Bioactive bacterial strains predominantly belong to Pseudoalteromonas spp [14], the Roseobacter clade [15], and Actinobacteria [16]. A number of marine derived antimicrobials have been characterized in greater detail, including halogenated and sulfuric compounds [17, 18], depsipeptides and lipopeptides [19, 20], glycolipids [21], as well as high
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