Screening of algal strains collected from NCR region for biopesticidal properties
Student name: Ms Arlene Asthana Ali
Guide: Dr Pallavi Somvanshi
Year of completion: 2013
Host Organisation: The Energy and Resource Institute (TERI), New Delhi
Supervisor (Host Organisation): Dr Neetika Walia Chhabra
Abstract: Algae, especially Cyanobacteria inhabit a range of diverse and extreme habitats and have
potential to produce an elaborate array of secondary metabolites with unusual structures and
potent bioactivity. Algal strains (Cyanobacteria and microalgae) isolated from terrestrial
habitats in Delhi NCR regions were evaluated for their biopesticidal properties against six
phytopathogenic fungi by Kirby-Bauer Disk Diffusion Susceptibility Test. The algal strains were
grown in BG-11 media ( both in nitrogen-free and nitrogen supplemented medium). Extracellular
and intracellular metabolites of fifty-six isolates were extracted from the supernatant culture
media and the cells using methanol. The intracellular extracts of two isolates, identified as
Westiellopsis prolifica and Westiellopsis species belonging to cyanobacteria and extracellular
extract of Westiellopsis species showed antimicrobial activity against the six fungi namely
Fusarium oxysporum f.sp. Lycopersici, Fusarium oxysporum f.sp. Cubense, Fusarium oxysporum
f.sp. Pisi, Fusarium oxysporum (isolated from panama wilt infested Banana field), Fusarium
oxysporum f.sp. Zingiberi and Pythium sp. Westiellopsis species showed greater antimicrobial
activity than Westiellopsis prolifica but both were found to be less efficient than the controls.
Spectral analysis of the antimicrobial extracts of W. prolifica and W.sps. showed that W. sps had
two extra compounds in the UV range which might have accounted for its increased
antimicrobial activity as compared to W. prolifica. Optimization of the two potential strains for
their biopesticidal property can be done for their further application as biocontrol agents.
Keywords: Cyanobacteria , microalgae, antimicrobial, phytopathogen, Kirby-Bauer Disk
Diffusion Susceptibility Test.
