Determination of growth, photosynthesis and gross chemical composition of Scenedesmus Obliquus (Turp) Kutz., and Chorella vulgaris Beij. in response to varying concentrations of phytohormones, molybdenum and copper

The growth and productivity of Scenedesmus obliquus (Torp.)Kutzing and Chorella vulgaris Beijernick was studied to evaluate the effects of exogenous application of IAA, Ki and ABA; and enhanced and starved MLA medium with MoO Sub 4- and Cu sup ++ on the production of protein, polysaccharide, beta 1,3-glucan and lipid content were investigated. Cultures of microalgae collected from the Murray River, Victoria, Australia that were maintained at the Beardall Laboratory, Monash University were used in this study. The cells were grown at 25 +- 0.5 deg C over a photoperiod of 12:12 with photon flux density 242.9 mum sup -2/s. Chlorella treated with IAA at 4 x 10 sup -9 M, Ki at 4 x 10 sup -4 M and ABA (4 x 10 sup -4 -4 x 10 sup -14 M) increased in growth rate by 1.6-2 fold compared to the control. Micronutrient-phytohormone combination was the best treatment to increase growth of Scenedesmus by 2.8 fold and Chlorella by 3.4 fold with Cu Sup ++ phytohormone. Dramatic upsurge of protein content during exponential phase is with ABA rising 2-folds in Senedesmus sand 10-folds in Chlorella. Scenedesmus during stationary stage increase 20-folds and 18-folds in Chlorella with Ki. Among the carbohydrates, beta 1-3 glucan can be best harvested during exponential and stationary period of growth of Scenedesmus and Chlorella with Ki and ABA (4X10 sup -4 -4 x 10 sup -14 M) increasing 25-folds. Exogenous application of ABA (4 x 10 Sup -9 M) increased lipid content of Scenedesmus at exponential phase by 100-folds and 18-folds during stationary stage, Phytohormones when combined resulted in 80-folds increase in Scenedesmus at exponential (Ki + ABA). Chlorella at exponential phase (IAA + ABA) enhances lipid by 30-folds and at stationary phase (Ki + ABA) 13-folds. Enhancing and starving MoO sub 4 sup -- and Cu sup ++ showed the highest lipid can be harvested during exponential phase is Scenedesmus by 40-folds and Chlorella by 70-folds. When micronutrients and phytohormones were combined at exponential phase, lipid rose to 50-folds in Scenedesmus (starved Cu sup ++ + Ki) and 80-folds Chlorella (starved MoO sup 4 sup -- + IAA). Exogenous IAA, Ki and ABA (4 x 10 sup -4 -4 x 10 sup -14 M) and improving MLA medium with MoO sub 4 - and Cu sup ++ influence growth rate positively; affecting photosynthetic efficiency but not compromising photosynthetic apparatus, and changing affinity for CCM. Lipid content is the lowest molecular composition generated by algal cells followed by protein, polysaccharide and beta 1,3-glucan. Scenedesmus and Chlorella have different response to alterations in the culture condition. These species can be sources of protein and beta 1,3-glucan for food and feed, and the evident increase TAGs of the cell can be use as alternative source for biodiesel.