Screening of Microorganisms from Deep-Sea Mud for Antarctic Krill (Euphausia superba) Fermentation and Evaluation of the Bioactive Compounds

• DOI: 10.1007/s12010-014-1403-3
• Publication Date: 2014-12-02T13:30:17Z
• Authors: Jianan Sun; Feifei Kan; Pei Liu; Shuai He; Haijin Mou; Changhu Xue; Xiangzhao Mao
• Keywords: 0301 basic medicine; China; Geologic Sediments; Bacteria; Oceans and Seas; Biphenyl Compounds; Biocompatible Materials; Free Radical Scavengers; Antioxidants; 03 medical and health sciences; Phenols; Picrates; Fermentation; Animals; 14. Life underwater; Amino Acids; Euphausiacea

Twelve kinds of strains were isolated from deep-sea mud which can use Antarctic krill powder as the sole carbon/nitrogen source. These strains were identified by 16s rDNA sequence analysis and grouped into eight different genera, including Bacillus, Shewanella, Psychrobacter, Klebsiella, Macrococcus, Aeromonas, Acinetobacter, and Saccharomyces. After fermentation of Antarctic krill powder using these strains, bioactive compounds including total phenolics, free amino acids, and enzyme activities were investigated. Meanwhile, antioxidant activities of the fermentation liquors were also detected. Results showed that bioactive compounds could be effectively produced through fermentation process by these strains, of which three strains (Bacillus subtilis OKF04, Macrococcus caseolyticus OKF09, and Aeromonas veronii OKF10) could produce more than 650 mg/L total phenolics or 2000 mg/L total free amino acids. In terms of enzyme activities, almost all of the strains showed protease activity and amylase activity, but only Bacillus cereus OKF01 and Bacillus megaterium OKF05 performed lipase activity and chitinase activity, respectively. All of the fermentation liquors showed antioxidant activity, within which Bacillus megaterium OKF05, Macrococcus caseolyticus OKF09, and Aeromonas veronii OKF10 displayed it more prominently. These results demonstrate that the Antarctic krill powder could be effectively converted by microorganisms isolated from deep-sea mud for production of bioactive compounds mixture.