Screening and enrichment of high lipid producing microalgal consortia.

Lipid content is the main parameter for the evaluation of microalgae towards biodiesel production. The present study was aimed at the screening of desirable algal consortia based on lipid content for further processing into biofuel. Twenty different algal consortia were investigated for lipid content qualitatively by Nile Red and quantitatively by gravimetric method and FTIR. Nile Red is used as a fluorophore for physically characterizing the lipid body in algal cultures. The yellow fluorescence in all the samples confirmed the presence of lipid content when observed under a fluorescent microscope. Lipid contents of algal consortia estimated by gravimetry varied from 3.53-16.21%, which was higher than that assessed by FTIR analysis. FTIR spectroscopy can be used for the quantitative estimation of lipid content, protein and carbohydrate concentration. FTIR analysis of the samples revealed the presence of lipid content by virtue of methylene and methyl stretching peaks at 2800-3000 cm-1. The appearance of stretching vibrations at 1600-1700 cm-1 and 1000-1200 cm -1 obtained by FTIR spectra confirmed the presence of protein contents and carbohydrate, respectively in all the samples. Two algal consortia SM 4 and SM13 were screened out on the basis of high lipid concentration. These algal samples can be further optimized for enhanced biofuel production.