Pengaruh Aerasi terhadap Produksi Biopestisida oleh Pseudomonas putida Menggunakan Substrat Limbah Cair Tahu

Abstract

Biopesticides is pesticide containing microorganism like bacteria, viruses, and fungal that are used to control pest. Biopesticides from endophitic bacteria are used to control nematode P. brachyurus. Endophitic bacteria are bacteria that colonize plant tissue without disturbing the plant. Pseudomonas putida is one of the endophitic bacteria that have the potency to control soil borne pathogen with antibiotics and siderophore from their activities. One of substrates that can be used as cultivation media is tofu waste. This waste come from filtration of soybean extract to make tofu through protein fractionation of soybean extract. This substrate contain organic material such as protein, fat, carbohydrate, and others which are useful for bacteria growth. One of the important factors for aerobic cultivation is aeration. The main function of aeration is as oxygen source to bacterial metabolism and homogenity on the medium. The objectives of this research are to produce biopesticides from Pseudomonas putida using tofu waste as substrate, and to determine aeration effect to bacteria biomass on production of biopesticides. The first step of this research is cultivation of medium test. The second step is preparation of inoculums using TSA (Tryptic soybean agar) and TSB (Tryptic soybean broth). After that the inoculums are cultivated on tofu waste substrate using bubble column bioreactor with aeration of 0,5, 1, 1,5 vvm. The parameters from this research are pH, OD (optical density), bacteria biomass dry weight, and residual sugar. The last step is toxicity test to nematode P. brachyurus. Completely randomized factorial design test with aeration as factor is used in this research The result showed that tofu waste can be used as substrate to P. putida growth to produce biopesticides. The highest biomass dry weight is 1,608 g/l which is obtained from cultivation with 1 vvm aeration after 36 hours and the lowest is 1,191 g/l from 0,5 vvm. The toxicity test of nematode P. brachyurus showed that the most effective treatment is using aeration 1 vvm. The percentage of nematode mortalitas is about 99%.