1Energy and Wetlands Research Group, Centre for Ecological Sciences [CES],
Indian Institute of Science, Bangalore – 560012, India.
2 Centre for Sustainable Technologies [CST], Indian Institute of Science.
3Centre for Infrastructure, Sustainable Transport and Urban Planning [CiSTUP],
Indian Institute of Science, Bangalore 560 012.
*Corresponding author:
trv@iisc.ac.in
Abstract
Fatty acid methyl ester (biodiesel) has been derived from oil present in algae through transesterification using
catalysts of acids, base, supercritical fluids, etc. These catalysts are corrosive and have been posing challenges of
contaminating the environment necessitating environmentally friendly and biodegradable catalysts such as enzyme
(lipase) based biocatalysts. In this study, fungal strains (endophytic/free spores) were isolated from an estuarine
ecosystem and screened for extracellular lipase activities. A novel fungal strain Cladosporium tenuissimum,
identified through molecular technique exhibited higher lipolytic ac- tivity among the isolates. The crude lipase
extracted from fungus was subjected to ammonium sulphate precipitation and purification using Superdex 200 gel
filtration chromatographic system. The molecular weight of purified lipase was found to be ~46 KDa and a specific
activity of 37.2 U/mg. Lipase activities attained stability and reached maximum at 60 C temperature and pH of 6. The
purified enzyme was used as a biological catalyst for enzymatic transesterification of oil obtained from an
indigenously iso- lated salt tolerant diatom Nitzschia punctata. Spectroscopic analysis on fatty acids and
Fatty Acid Methyl Esters derived from diatom exhibited similarities in specific functional groups between algal oil
and biodiesel. Comparisons on biodiesel yield estimation and FAME compositions of enzyme catalyzed, acid catalyzed
biodiesel assessed through gas chromatographic techniques revealed a higher efficiency (87.2 ± 0.47%) of biocatalysts
compared to conventional acid catalyst (83.02 ± 0.35%) exhibiting potential scope for large scale application of
environment friendly biocatalysts to enhance the conversion per- formances of the transesterification process.
Citation :
Saranya G and Ramachandra T V, 2020. Novel biocatalyst for optimal biodiesel production from
diatoms, Renewable Energy, Volume 153, June 2020, Pages 919-934,
https://doi.org/10.1016/j.renene.2020.02.053