Production and characterization of bioactive metabolites from piezotolerant deep sea fungus Nigrospora sp. in submerged fermentation.
OBJECTIVE
To produce and characterize bioactive metabolites from piezotolerant marine fungus Nigrospora sp. in submerged fermentation.


RESULTS
A distinct marine strain, Nigrospora sp. NIOT has been isolated from a depth of 800 m at the Arabian Sea. The 18S rRNA and internal transcribed spacers (ITS) analysis demonstrates its close association with the genus Nigrospora. Effect of pH, temperature, salinity, carbon source and amino acids was studied to optimize the fermentation conditions. Optimal mycelia growth and secondary metabolites production were observed at 6·0-8·0 pH, 20-30°C temperature, 7·5% salinity, sucrose as carbon source and tryptophan as amino acid source. The extracellular secondary metabolites exhibited high antimicrobial activities against both gram-positive and gram-negative pathogenic bacteria with minimal inhibitory concentration (MIC) values higher than 30 μg ml(-1). Strongest cytotoxicity was observed in all cell lines tested, GI50 (growth inhibition by 50%) was calculated to be 1·35, 3·2, 0·13 and 0·35 μg ml(-1) against U937, MCF-7, A673 and Jurkat, respectively. Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) analyses of secondary metabolites confirmed the production of antimicrobial and anticancer substances.


CONCLUSIONS
A piezotolerant fungus Nigrospora sp. NIOT isolated from deep sea environment was successfully cultured under submerged fermentation. The secondary metabolites produced from this organism showed potent antimicrobial and anticancer activities with immediate application to cosmetics and pharmaceutical industries.


CONCLUSIONS
This is the first study exploring Nigrospora sp. from 800 m in marine environment. This deep sea fungus under optimized culture conditions effectively produced bioactive secondary metabolites such as griseofulvin, spirobenzofuran and pyrone derivatives at higher concentrations.
Marine Biotechnology Division, Ocean Science and Technology for Islands Group, ESSO-National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, India.
G K
GK
Arumugam
S K
SK
Srinivasan
G
G
Joshi
D
D
Gopal
K
K
Ramalingam
D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000378:metabolism / Q000633:toxicity; D001203:Ascomycota / Q000145:classification / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D005285:Fermentation; D006801:Humans; D019169:Jurkat Cells; D061986:MCF-7 Cells; D008969:Molecular Sequence Data; D011312:Pressure; D012623:Seawater / Q000382:microbiology*; D064210:Secondary Metabolism
D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents
Nigrospora; anticancer; antimicrobial; marine fungus; submerged fermentation