Judul: Komposisi Media Produksi Pseudomonas stutzeri IRNAE dan Bacillus sp. L TS 40 dan .Formulasinya untuk Probiotik pada Tambak Udang.
Abstrak: Shrimp production in Indonesia has been decreased since 1990. Factors that influences decreasing of shrimp production are decreasing of water quality and ~reasing of diseases. One imfortant bacterial shrimp disease is vibriosis ~ases. One alternative way to solve this disease problem is by application of bfcterial probiotics. Bacterial probiotics used in this research were Pseudomonas s~tzeri IRNAE and Bacillus sp. LTS 40. Molase was used as a carbon source 'IDereas soybean meal and urea were used as nitrogen source for media ti:>duction of the probiotics. The media were enriched with TSP. The results s~owed that the best media composition for growth of Pseudomonas stutzeri IB:NAE was combination of molase, soybean meal, urea 0,1% and TSP 0,5%, ~ile the best media composition for growth of Bacillus sp. L TS 40 was ~bination of molase, soybean meal, TSP 0,1%. Application of the isolates in ~imp culture showed that ideal formulation of the probiotics was Pseudomonas s'fj;tzeri IRNAE and Bacillus sp. with rasio of 2: 1 (v/v). And the survival rate (SR) of the shrimp was 51 % .
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Judul: Optimizing media for Bacteriosin Production by Bacillus sp. Strain LTS 40 Isolated from Shrimp Pond.
Abstrak: Export demand on shrimp as fishery commodity has increased. However, nowadays Vibriosis diseases caused by fluorescent bacterium Vibrio harveyi have decreased shrimp production. Probiotic bacteria can be used as biocontrol to inhibit the growth of V. harveyi in ponds. Bacillus sp. LTS 40 as a probiotic candidate was able to produce bacteriosin inhibiting the growth of V. harveyi. Production of bacterial probiotics should be low cost using a cheap media. Media production of bacterial probiotics commonly use molase as carbon sources and fertilizers such as NPK, ZA, and urea as a source of nitrogen. The aim of this research was to get the best media composition for growth of Bacillus sp. LTS 40 in producing bacteriosin. Antimicrobial activity test showed that Bacillus sp. LTS 40 could inhibit the growth of V. harveyi with inhibition index of 1,08. Competition assay in liquid culture also showed that Bacillus sp. LTS 40 could inhibit V. harveyi up to 100% at 24 hours, 48 hours, and 72 hours of incubation. Bacillus sp. LTS 40 had a good growth on media composition of 0,2% molase and NPK. In 10 liter fermentor, bacteriosin was produced during exponential phase and optimum production was at 36 hours of incubation with inhibition zone of 15.25 mm. This result showed that Bacillus sp. LTS 40 can be used as probiotics to reduce mortality of shrimp larvae caused by V. harveyi in shrimp cultures. Key words: Bacillus sp., V. harveyi, bacteriosin
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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