THE EFFECT OF TEMPERATURE AND NITRATE COMPOUND ON GROWTH, BIOMASS AND FREE FATTY ACID CONTENT ON MICROALGAE CULTURE OF Spirulina sp. and Skeletonema sp.

Temperature and availability nutrients played an important role on growth and lipid production of microalgae. In this study, we examined the effect of increasing suhu and excessed and depleted NO3 on growth rate, biomass and free fatty acid concentration in the Spirulina sp and Skeletonema sp. Two microalgae were culture on Conway and Milne media for 21 days using continuous culture technique. There were four temperature treatments, such as 28oC, 30oC, 32oC and 34oC and three nutrient treatments, which were control nutrient treatment, without NO3 and two times NO3 concentrations from control treatments with three replicates for each treatments. Results found that increasing temperature significantly affected on biomass and concentration free fatty acid, meanwhile nutrient treatments affected on growth rate, biomass and concentration of organic Carbon. In general, increasing temperature was more affected on Spirulina sp in terms of increasing growth rate, biomass and free fatty acid concentration. However, Skeletonema sp was more responsive to availability of NO3 in the media culture for increasing free fatty acid, and percentage of free fatty acid per dry weight.

Free Fatty Acid Concentration and Carboxy methyl cellulase Activity of Some Formulas of Protected Fat-proteins Tested In Vitro

The aim of this study was to determine the levels of free fatty acids and carboxymethylcellulase activity (cmc-ase) activity of some protected fat-proteins base on in vitro Tilley and Terry method. Two sources of fat, i.e. crude palm oil and fish oil and three sources of protein i.e. skim milk, soybean flour and soybean meal were used in the formulation of protected fat-protein, and thus there were six treatment combinations. The filtrate from the in vitro test was analyzed for the levels of free fatty acids and cmcase activity. The result of this research indicates that different combinations of feed materials and fat give different content of free fatty acid in first stage and second stage in vitro, with the best results in the combination treatment of skim milk and palm oil that give the lowest result of free fatty acid concentration in fisrt stage in vitro (0.168%) and the highest result free fatty acid concentration in second stage in vitro ( 4.312%) . The activity of CMC-ase was not influenced by different sources of fat and protein. It can be concluded was that the protection of the combination between skim milk and CPO gives the highest protection results.