| dc.description.abstract | Desaturase is the catalyst for the formation of the double bond carbon chains either monounsaturated fatty acids (MUFA) or polyunsaturated fatty acid (PUFA). Desaturase producing fungi can be used to increase the unsaturation of crude palm oil (CPO). In the present study the fungi used was Rhizopus oryzae, because it is edible. The purpose of this study was to test the ability of Rhizopus oryzae in producing desaturase, extending enzyme-substrarate contact time, and increasing unsaturation of crude palm oil using bioreactor system model of spiral hose with height variation. First, the fungi were cultured in liquid media with supplements containing certain salts and CPO using Erlenmeyer. After incubation, the culture supernatant was separated from the biomass (liquid fermentation). Liquid fermentation was transferred into a bioreactor system model of continuous spiral hose with height variations (50 cm, 100 cm, 150 cm, 200 cm and 250 cm). Palm oil was pumped from the bottom of the column using a peristaltic pump. CPO was then characterized by determining the iodine number, saponification number, acid number and fatty acid composition both before and after the bioconversion. The results showed that Rhizopus oryzae fermentation liquid was able to increase the unsaturation CPO and multiple unsaturated fatty acid content. On studied conditions, the maximum unsaturation increase occurred at a height of 200 cm with iodine value change of 17.091 g I2/100g CPO with the contact time for 35 minutes. This indicated that the longer the contact time, the higher the unsaturation of CPO. Iodine number could also decrease due to the oxidation of the C = C double bond, that was indicated from the results of iodine number at a height of 250 cm with iodine value change of 15.886 g I2/100g CPO for contact time of 47 minutes. At the optimum conditions, the saponification number was 183.489 g KOH/g CPO and acid number was 9.36 g KOH/g CPO with levels of free fatty acids (% FFA) of 0.936%. Fatty acid composition of palm oil after optimum bioconversion conditions showed increase in oleic acid, and linoleic acid. | en |
