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.
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Judul: Penentuan Rasio C/N dan Pengembangan Produksi Bioinsektisida oleh Bacillus thuringiensis Menggunakan Media Kultivasi Limbah Industri Tahu
Abstrak: Development and application of local product biopesticide, especially based on B. thuringiensis (Bt) still has been considerable potential. This is supported by the local availability of Bt local strains and agro-based raw materials are abundant and not expensive. Research toward utilization of industrial waste of tofu as a medium of cultivation of Bt has been done. In the early stages the Bt strains are isolated and selected. Bt B2 bacteria from the culture collection, protein crystals form bipiramid and cubes, are strains with the highest toxicity against C. binotalis. The optimization of media formulation is performed on a scale of 500 ml with a variation of C/N ratio 3:1, 5:1, 7:1, 9:1 and 11:1. B2 strains provides optimum toxicity value at C/N ratio 7:1 with LC50 value of 0.90 mg/L or 8356 IU/mg. The results of cultivation on the bioreactor 3 L shows substrate utilization efficiency of 67.77 % with LC50 value of 3.56 g/ml or 2112 IU/mg. Characterization of δ-endotoxin with SDS-PAGE indicates protein pattern at all media formulations contain genes Cry 1 (144 kD) and Cry 2 (66.80 kD and 55.51 kD) and Cyt1Aa (25.27). Amino acid δ-endotoxin in 500 ml scale cultivation and 3 L bioreactor show the same composition as many as 15 kinds of amino acids but the quantity of amino acids on the 3 L bioreactor scale smaller than which on 500 ml. Determination of physical factors for the increasing scale on the 40 L bioreactor using a base power per unit volume (Pg/V) still provide power value per unit volume (Pg/V) of 0.037 HP/m3 (weak level of agitation impellers), aeration requirement is 0.7 VVM with agitation speed 111.57 rpm. Cultivation at 40 L bioreactor run at a pH range from 6.5 to 7.0 where the total number of maximum cells is 10.35± 0.03 x 10 8 cfu/ml with a maximum cell growth rate of 0.48 ± 0.01 hours-1, while the number of the highest spore of 3.90±0.06 x 108 cfu/ml with a maximum rate of spore growth is 0.25 ± 0.01 hours-1. Substrate utilization efficiency at 68.21 % with LC50 values is 3.19 g/ml or 2357 IU/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