Produksi Inulinase Ekstraseluler Dari Aspergillus Niger Gmn 11.1 Yang Diisolasi Dari Umbi Dahlia (Dahlia Variabilis)

Abstract

Inulin, a polyfmctan, is found as the resci-ve carbohydrate in the roots and tubers of various plants (i.e. Jerusalem artichoke, chicory and dahlia tubers). Enzymatic hydrolysis of inulin produce syrup up to 95% fructose, fligh fructose svTup can be used as low caloric sweetener because fructose is 1.5 to 2 times sweeter than sucrose. P-fructofuranosidase (inulinase) from the mold Aspergillus niger Gmn 11.1 is of interest because of its industrial potential in fmctose syrup production . Inulinase production from Aspergillus niger Gmn 11.1, isolated from dahlia tubers by using six different media composition was produced by batch-culture. Inulinase activity is determined by measuring reduction sugar by using oitotoluidin method. The best result is found by using composition of medium III (inulin 1 % + (NH4)2 HPO4 0.5 % + MgS04 7H2O 0.05 %). The highest inulinase activity was 7.8107 x 10"^ mmol/ml/'minute, and incubation time sixt>' hours by using statistic analysis base on DMRT. Ba.se on composition of the best medium (medium III) by variating of the carbon source (inulin, starch, cellulose, fructose and glycerol), pH fermentation (4.5, 5.0, 5.5 and 6.0), and temperature (30°C, 40"C, and 50° C) and incubation time sixt>' hours is found that the highest inulinase activity 3.1228 mmol'ml/minute was obtained under optimum condition pH 4.5 and temperature 50° C with inulia as the best inducer.