OPTIMASI MEDIA FERMENTASI Aspergillus oryzae, PENGHASIL ANTIJAMUR PATOGEN BUAH KAKAO Phytophthora palmivora Fermentation Medium Optimization of Aspergillus oryzae, Antifungals Producer for Cacao Pathogen Phytophthora palmivora

Abstract

Indonesia was known as a producer and exporter of cacao, but nowadays Indonesia had an issue in cacao production caused by microorganisms (Phytophtora palmivora) that capable of reducing the amount of cacao production each year. This study follows up a previous study that had found compounds that are actively against at Phytophtora palmivora from Aspergillus oryzae metabolites. In this study the compound will be produced in greater numbers to optimize fermentation medium. The first stage was conducted to determine the profile of the active compound and to analyze the best carbon, nitrogen source for Aspergillus oryzae fermentation medium. The second stage was designed by using Response Surface Method (RSM) with Central Composite Design (CCD) to optimize two variables in the fermentation medium, glucose concentration (the best carbon source) and the concentration of peptone (best nitrogen source). The expected response was the most active compounds percentage of the area. Data analysis was performed by Design Expert DX 7.1.5 program. The first stage of this study presumed that Tenuazonic acid compounds with a molecular weight of 198.1126 gram.mol was an antifungal compound produced by Aspergillus oryzae fungus to prevent Phythopthora palmivora fungus pathogens cacao pods. In addition the results are that glucose was the best carbon source (mean % relative area of antifungal compounds: 85.39%) and that peptone was selected as the best source of nitrogen (mean % relative area of antifungal compounds: 91.07%). The second stage showed the optimum conditions of fermentation medium antifungal Aspergillus oryzae was the composition of glucose 35.25 g/L and peptone 16.7 g/L. The combination of both compositions would yield a mean response of laboratory data % relative area of antifungal compounds 91.2217% and the estimated value (prediction) by Design Expert models 92.2936%. Difference in the estimated values (the response of the model) to the value of the results of response in laboratory experiments at 1.1614%, then it could be concluded that the model used was appropriate and able to explain the applied experimentaldata.-1Kata kunci: Cacao, Aspergillus oryzae, Phytophtora palmivora, active compound, optimization of fermentation medium, Response Surface Method (RSM)