Shahila, NilaAhmad AdriantoWisrayetti2012-10-292012-10-292012-10-29rio andikahttp://repository.unri.ac.id:80/handle/123456789/302Solid waste that is produced by palm industry in Indonesia has reached 15.20 million ton waste/year. One of them is waste of fibre palm fruit. It will pollute the invironment if it is not carried out preferable. Managing the waste into compost manure is one of the solutions. The purpose of this researce is to identify the influence of starter concentration in composting process an to get the ratio of C/N optimum in making compost by using biofertilizer technology. Biofertilizer is one of technology that uses microorganism to increase the fertility of soil in the process of composting by using the content of microorganism in the form of nutrition. This research consist of 4 steps. First step is preparing the starter. Second step is preparing the substrate in the form of solid waste of fibre palm fruit in 2 cm size. Third step is preparing bioreactor by using 5 bioreactors. Fourth step is composting process with variation starter concentration. During the composting process, measuring pH, temperature, moisture and aeration are done in each bioreactor performed every 3 days. Composting is done with aerobic process. The results showed that the concentration of nitrogen starter 0% of 0.94 is obtained, 10% at 1.09, 20% of 1.31, 30% 0f 0.83 and 40% 0f 1.07. Based on the results, the optimum value for nitrogen in the composting process requirements contained in the starter 20% concentration can accelerate the activity of microorganism to the value of the ratio C/N at 10.45 on day 60 with a 20% concentration of starter. Thus, the value of the ratio C/N is obtained in accordance with the standards of quality compost SNI 19730-2004.otherBiofertilizercompostpalm fruit fiberArticle