Judul: Study of scale up for bioinsecticides production from Bacillus thuringiensis aizawai using liquid waste industrial tofu and coconut water substrate
Abstrak: Bacillus thuringiensis aizawai is one type of bacteria which often used in the production of microbial bioinsecticide because this patties very effective in controlling larvae of Lepidoptera and Diptera, especially the leaf caterpillar pests of cabbage and other vegetables. The use of biopesticides in Indonesia is still rarely because bioinsecticide marketed in Indonesia is still an import product so that price is relatively expensive. This problem can be overcome with producing bioinsecticide contain active Bacillus thuringiensis aizawai using local raw materials such as liquid waste industrial tofu and coconut water. The objectives of this research was to study the scale up based on the optimum conditions for growth of Bacillus thuringiensis subsp. aizawai in pilot and industrial scale in the production of bioinsecticide microbial use of liquid waste of industrial tofu and coconut water. Carbon-nitrogen ratio in this research is (7:1), with 80 : 20 composition of liquid waste of industrial tofu and coconut water, the starter added 10% (v/v), cultivation time during 72 hours and using fermentors 3 and 40 liters. The highest toxicity of the product can be obtained through bioassay test to larvae Croccidolomia pavonana and the highest toxicity levels is at 48 hours fermentation with LC50 value of 0.01 mg/L. The result showed that by 0.01 mg/L bioinsecticide microbial could kill 50% of the target insect. Range of pH value from 5.25.-7.23, and the highest total plate count (TPC) is 1.44 x 107 CFU/ml in the fermentor with a capacity of 40 litres. The highest viable spore count (VSC) is 8.03 x 105 spores/ml in fermentor with a capacity of 40 litres with cultivation 72 hours. The calculation of the scale up on industrial scale fermentor 10,000 L showed that the needs of Pg/V are 0.0256 HP/m3 per second, a rate of aeration: 0.27 VVM and agitation speed: 0.47 rps. Based on the similarity of geometry fermentor 10,000 litres, fermentor has tank diameter: 2.09 m and impeller diameter: 0.85 m with a working volume of 7,000 litres.
Keyword: 

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.
Keyword: 

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