Optimization of Culture conditions and extraction protocols For the enhanced production of zeaxanthin From marine cyanophycean and chlorophycean Microalgae

Abstract

Microalgae are a diverse group of photosynthetic organisms gaining newlineattention as impending source of high value biomolecules like pigments, lipids, newlinepolysaccharides and biodiesel. The present study focused on algal-derived newlinexanthophyll carotenoid zeaxanthin, which is widely used as a nutraceutical for newlineits ability to prevent age associated macular degeneration (AMD), cataract and newlinenight blindness. Zeaxanthin along with lutein are concentrated in the eye macula newlineand possess strong antioxidant and anti tumour properties. newlineThe prime focus of the study dwelled on identifying the strains with newlinepotential biomass and zeaxanthin production capability of marine newlinecyanophyceans and chlorophyceans. Subsequent to preliminary screening newlineexperiments, the study identified one chlorophycean (Dunaliella tertiolecta) newlineand two cyanophycean algae (Trichodesmium thiebautii and Synechococcus newlinemarinus) as prospective strains for further optimization studies. Both upstream newlineprocess of optimizing culture medium nutrient components and downstream newlineextraction processes were optimized using statistical tools, like Plackett- newlineBurman and response surface methodology. newlineThe results revealed statistically optimized Artificial Sea water Nutrient newline(ASN III) medium accelerated zeaxanthin production from T. thiebautii by 2.33 newlinefold and biomass accumulation by 2.23 fold by manipulating the concentration newlineof four significant nutrient factors of ASN III culture medium namely sodium newlinenitrate, magnesium sulphate heptahydrate, disodium EDTA and sodium newlinecarbonate. Similarly, BG 11 growth medium was statistically amended using newlinetwo step advanced optimization strategy by varying the concentrations of three newlineviii newlinenutrient components, namely sodium nitrate, disodium EDTA and dipotassium newlinehydrogen phosphate for increasing zeaxanthin accumulation by the blue green newlinemicroalga S. marinus, which elevated zeaxanthin accumulation upto 8.49 fold newlineand biomass production upto 2.98 fold than the unoptimized growth medium. newlineAdditionally, De Walne s medium was statistically modified by varying the newlineco