Growth kinetics and 36K Isolate Protease Activity of Mangrove Ecosystem Sediment Karimunjawa, Jepara

Marine and brackishwater culture produced large number of organic waste, mostly from leftover feed and faeces, which normally released to the nearby water system and becoming source of deseases and reducing water quality. The study was aimed to determine the growth kinetics and protease activity of 36k isolate from mangrove sediment of Karimunjawa, Jepara which possibly developed into probiotic consortium candidate with bioremediation activity capability. The study was able to describe the growth kinetics and protease activity of 36k isolate which has lag phase (adaptation) on the 0 to the first 4 hours. Meanwhile from 6th to 30th hours isolate 36k entering logarithmic phase (exponential) characterized by significant growth. At the 30th hours period the OD value was 1,939±0,0125, bacterial biomass dry weight of 1,325±0,043 mg.ml^-1, specific growth rate (μ) was 0,1446 hours, number of generation 8,7609 dan regeneration time of 4,794 hour. Between 36 to 42 hours the growth of 36k isolate cell was relatively no difference indicating the stationer phase has reached followed by mortality phase between the 42–48 hours where the growth rate was decline due to the limitation of growth material such as vitamins and minerals. The result also show that protein consentration was significantly decline up to 97,365%. The reduction of of protein content was 0,255±0,005 mg.ml^-1.hour^-1. The production of enzyme in cultured bacteria was conducted between first 2–6 hours and reach the optimum activity by 6 hours incubation i.e. at the exponential growth phase. The substrate consumption by 36K bacteria isolate was indicated by the decline of reduced sugar with average rate of substrate consumption of 2,0557 g.g^-1.