Judul: Formulasi Produk dan Penurunan Mutu selama Penyimpanan Bioinsektisida Bacillus Thuringiensis subsp. aizawai dari Limbah Industri Tahu
Abstrak: Bioinsecticide can kill insects and disease vector. Bioinsecticide developed from bacteria, virus, mushroom, and protozoa. Bacteria that often used to produce bioinsecticide is “Bacillus thuringiensis”. Bacillus thuringiensis subsp. aizawai (Bta) as one of the Bacillus thuringiensis (Bt) species produces crystal protein called delta endotoxin (δ-endotoxin). As other Bt crystal protein, this crystal is specifically toxic to larvae Lepidoptera and Dipteral ordo. One of advantage bioinsecticide Bta is savety for our environment. Therefore, in this research produce bioinsecticide Bta from waste of industrial tofu as raw material standard. This research was to obtain the best product formulations Bta, reduction quality Bta, and to asses the level of toxicity Bta during storage. Media formulation using tofu waste and tofu waste water, with a ratio of 20: 80 and the starter added 10 (% v /v). In this research, product formulation using lactose as filler. The highest viable spore count (VSC) is the product formulation of freeze lactose (1.45 x 108 spora/mg), whereas the lowest VSC is the product formulation of freeze without lactose (9.25 x 107 spora/mg). After storage one month, the highest VSC is product formulation of freeze lactose was storaged on temperature 5 oC (9 x 106 spora/mg), whereas the lowest VSC is the product formulation of freeze without lactose was storaged on temperature 35 oC (1.5 x 106 spora/mg. The level toxicity (LC50) product formulation of freeze lactose and freeze without lactose are 0.25 mg/l. Value of LC50 from all of the treatment higher than value of LC50 Bactospeine (0.05 mg/l). During storage one month, value of LC50 and potential product bioinsecticide Bta go down continually.
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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