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: 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