Received: 7 September, 2011. Accepted: 10 November, 2012. Original Research Paper Dynamic Biochemistry, Process Biotechnology and Molecular Biology ©2012 Global Science Books Influence of Different Culture Conditions on Yield of Biomass and Value Added Products in Microalgae Sarada Ravi * • Ranga Rao Ambati • Sandesh B. Kamath • Dayananda Chandrappa • Anila Narayanan • Vikas S. Chauhan • Gokare A. Ravishankar Plant Cell Biotechnology Department, CSIR - Central Food Technological Research Institute (CFTRI), Mysore – 570020, India Corresponding author: * sarada_ravi@yahoo.com; sarada@cftri.res.in ABSTRACT Microalgae viz., Botryococcus, Haematococcus and Dunaliella, were studied for their adaptability to different culture conditions. Botryococcus strains of indigenous origin and culture collection centres were studied for their growth, hydrocarbon and lipid profile and for their biomass yields under different bicarbonate concentrations. Growth of Haematococcus was compared in autotrophic (ambient and enriched CO 2 atmosphere) and heterotrophic culture conditions. Influence of ammonium salts, urea and commercial fertilizers as nitrogen source under autotrophic conditions and different amino acids as nitrogen source under heterotrophic culture conditions, was studied on growth and astaxanthin content of Haematococcus. Influence of different salinities was studied on growth and -Carotene content of Dunaliella in AS100 and De Walnes media. Results indicated that Botryococcus strains varied in their biomass yields (0.25-2 g L -1 ), hydrocarbon content (15-60% w/w) and lipid content (15-30%, w/w). An indigenous strain was able to grow at all the tested concentra- tions of bicarbonate with maximum biomass yield at 0.25 g L -1 . The growth rate of Haematococcus was higher in heterotrophic medium with a cell count of 41-44 × 10 4 on 5 th day after inoculation. The supplementation of autotrophic medium with 2% CO 2 led to a 4-fold increase in cell count. Use of DAP as nitrogen source showed a 20% increase in yield of encysted biomass. Both DAP and Suphala led to astaxanthin productivity of 46-48 g L -1 . Haematococcus was able to utilize all the amino acids at tested concentrations in heterotrophic culture conditions. Enhanced growth of Dunaliella was observed at 1.0 M NaCl concentration in both the AS 100 and De Walnes media while 2.0M NaCl in De Walnes medium showed higher -carotene content (45.6 mg g -1 ). _____________________________________________________________________________________________________________ Keywords: Botryococcus, carotenoids, Dunaliella, fatty acids, Haematococcus, hydrocarbons Abbreviations: DAP, diammonim phosphate; BBM, Bold’s basal medium; HPLC, high performance liquid chromatography; GC, gas chromatography; MS, mass spectrometry; FAME, fatty acid methyl esters; FID, flame ionization detector; NIST, National Institute of Standards, USA INTRODUCTION Microalgae are known as a source of value added com- pounds of nutraceutical, pharmaceutical and biochemical applications. Although several micro algal species are known taxonomically, their biochemical evaluation for high value metabolites is limited to very few species and when it comes to commercial exploitation, only a few of the orga- nisms like Spirulina, Chlorella, Dunaliella, Haematococcus, Porphyridium, Phaeodactylum, Crypthecodinium, etc. are being cultivated at large scale for food supplements, feed ingredients and for cosmetic and pharmaceutical applica- tions. In recent years exploration of microalgae for hydro- carbon and oil production has gained importance due to rise in crude oil prices and limited fossil fuel resources (Chisti 2008; Raja et al. 2008; Milledge et al. 2011). Although algae are known to grow in waste water and some species are used in treatment of waste water, their potential as energy source has not been exploited. In the present scenario of energy crisis and global warming, microalgae are gaining importance as renewable resource for energy and CO 2 sequestration. In view of this, attempts were made to evaluate microalgal strains of Botryococcus, Haematococcus and Dunaliella for production of hydro- carbon, lipid and value added products. The strains were evaluated for their adaptability to varying concentrations of bicarbonate in growth media, heterotrophic growth con- ditions, different organic and inorganic nitrogen sources and salinity conditions. Botryococcus braunii, a colonial chlorophycean is known to produce large amounts of hydrocarbons (Metzger et al. 2005; Dayananda et al. 2010; Ranga Rao et al. 2012). B.braunii species are grouped into A, B and L races based on the type of hydrocarbons they produce (Metzger et al. 2005). Race A produces C 23 to C 33 odd numbered n-alka- dienes, mono-, tri-, tetra-, and pentenes and are derived from fatty acids. The B race produces two types of triter- penes called botryococcenes of C 30 – C 37 as major hydro- carbons and small amounts of methyl branched squalene (Achitouv et al. 2004). The L race produces a single hydro- carbon C 40-78 , a tetraterpene known as lycopadiene. B. braunii is a promising renewable resource for the produc- tion of hydrocarbons and it has been reported that on hydro- cracking, the distillate yields 67% gasoline, 15%, aviation turbine fuel, 15% diesel fuel and 3% residual oil (Hillen et al. 1982). B. braunii is also known to produce varying amount of ether lipids, the quantity and composition of which varies with species and also among the races (Metz- ger and Largeau 2005). Strains of B. braunii Races are known to produce exopolysaccharides which may be up to 250 g m 3 in strains of ‘A’ and ‘B’ race and up to 1 kg m 3 in strains of ‘L’ race (Banerjee et al. 2002; Niehaus et al. 2011). Large scale cultivation of B. braunii will also con- tribute towards CO 2 sequestration (Sawayama et al. 1999; Tanoi et al. 2011). B. braunii strains have been shown to be adaptable to outdoor culture conditions in circular and race- way ponds indicating the potential for their mass cultivation. However, improving the hydrocarbon content in outdoor conditions remains a challenge (Ranga Rao et al. 2012). The focus of present study is to evaluate growth, hydrocar- bon and fatty acid profile of different strains of B. braunii, in response to different concentrations of bicarbonate. ®