Judul: Kajian rasio C/N terhadap produksi bioinsektisida dari Bacillus thuringiensis subsp. aizawai menggunakan substrat limbah cair tahu dan air kelapa
Abstrak: Bioinsecticide is an active substance from biological agent that kills insects and disease vector. Bioinsecticide or microbial insecticide can be developed from bacteria, virus, mushroom, and protozoa. Bacteria that often used to produce bioinsecticide is Bacillus thuringiensis (B.t). Bacillus thuringiensis subsp. aizawai (B.t.a) as one of Bacillus thuringiensis species produces crystal protein called delta endotoxin (δ-endotoxin). As other B.t crystal protein, this crystal protein is specifically toxic to larvae Lepidoptera and Diptera. Bioinsecticide is an alternatif solution, because it cannot cause pests resistance, does not make residue to the environment and does not kill non target organisms. This research aims to produce an active material bioinsecticide that is produced by B.t.a using tofu liquid waste and coconut water, which is cheap material can be used as nitrogen and carbon sources and it has protein, vitamin, mineral that are needed by microorganism to grow. Coconut water as fermentable sugar in fermentation bioinsecticide. The specific objective of this research is to obtain the best media formulation with optimal C/N ratio for bioinsecticide production. Carbon-nitrogen ratios in this research are A (3:1), B (5:1), C(7:1), D (9:1), and E (11:1), with 80 : 20 composition of liquid waste of industrial tofu and coconut water, the starter added 10 (%v/v) and cultivation time during 0-72 hours. The highest toxicity of the product can be resulted through bioassay test to Crocidolomia pavonana (C. binotalis) larvae instar-II. The pH value and weight of dry biomass during cultivation was increased while total sugars and OD (Optical Density) is decreased. Range of pH value from 6.5-7.96. For cultivation 0 hours the highest of dry cell biomass is media A (C/N=3:1) 0.60 g/L whereas the lowest is media B (C:N=5:1) and C (C/N=7:1) 0.40 g/L and for cultivation 72 hours the highest of biomass is media C (C/N=7:1) 15.90 g/L whereas the lowest is media A (C/N=3:1) 7.55 g/L. For cultivation 0 hours the highest OD is media D (C/N=9:1) 0.0214 and the end of cultivation the highest OD is media B (C/N=5:1) 2.91. The highest total plate count (TPC) is media C (C/N=7:1) 2.8 x 108 cell/ml or 7.40 cfu/ml in cultivation 48 hours whereas the lowest is media B (C/N=5:1) 1.19 x 107 cell/ml or 6.68 cfu/ml in cultivation 0 hours. The highest viable spore count (VSC) is media D (C/N=9:1) 5.63 x 106 spore/ml in cultivation 48 hours whereas the lowest is media C (C/N=7:1) 2.85x 106 spore/ml in cultivation 24 hours. The highest level toxicity (LC50) is media C (C/N=7:1) 0.01 mg/L in cultivation 48 hours and potential product is 80,000 IU/mg. The level toxicity (LC50) is contrary to potential product.
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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