Judul: Pengaruh Aerasi terhadap Produksi Biopestisida oleh Pseudomonas putida Menggunakan Substrat Limbah Cair Tahu
Abstrak: 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%.
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Judul: Produksi Bioinsektisida Dari Bacillus thuringiensis subsp. aizawai Menggunakan Limbah Industri Tahu Sebagai Substrat.
Abstrak: This research was to obtain the best media formulation oftions for bioinsectisides production using Bacillus thuringiensis subsp. aizawai and to asses the level of toxicity against larvae Crocidolomia binotalis (cabbage worms). Media formulation oftions using tofu waste and tofu waste water, with a ratio of 20: 80, 30: 70, and 40: 60 and the amount of starters added 10, 15, and 20 (% v /v). Observations done at 0, 30, and 48 hours of the cultivation time which include pH, total residual sugar, the total plate count, and the viable spore count. Toxicity tests were conducted by bioassay using larvae Crocidolomia binotalis (cabbage worms). The analysis of raw materials obtained on the carbon content of tofu waste and tofu waste water at 5.64% (wb) and 0.27% (wb), while the nitrogen content of 0.42% (wb) and 0.02% (wb). During the cultivation, the pH in the cultivation liquid was increased while total sugars is decreased. The pH values during cultivation was ranging from 7.27 to 8.21. Efficient use of substrate for cultivation 30 hours ranged from 13.14% (C2) to 33.61% (A3) and for cultivation 48 hours ranged from 31.73% (C3) to 41.91% (B3). The highest total plate count in this research is media formulation of B3 (2.14 x 108 cells/ml) with cultivation time during the 48 hours, whereas the lowest total plate count in this research is media formulation of A3 (1 x 107 cells/ml) with cultivation time during the 48 hours. The highest amount of viable spore count in this research is the media formulation of B2 (2.95 x 107 spores/ml) with cultivation time during the 48 hours, whereas the lowest viable spore count in this research is the media formulation of A1 (1.25 x 106 spores/mL) with cultivation time during the 48 hours. Cultivation during 30 hours using media formula A1 produces crystal protein in high toxicity to Croccidolomia binotalis larva. This is indicated by the highest toxicity level from bioassay test which shown by medium formulae of A1, which was 1,34 mg/L, and the lowest toxicity level was shown by media formulae of C3, which was 174,16 mg/L. Whereas cultivation during 48 hours using media formulation of A2 produces crystal protein in high toxicity to Croccidolomia binotalis larva. This is indicated by the highest toxicity level from bioassay test which shown by medium formulae of A1, which was 7,44 mg/L, and the lowest toxicity level was shown by media formulae of C3, which was 45636,00 mg/L. In the control (distilled water + prostiker) who were not given fluids bioinsectiside products not found of C. binotalis larva is dead, while in the commercial product (Bactospeine) toxicity was obtained at 0.05 mg / L with potential products 16 000 UI / mg.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular