Judul: Produksi protein empat isolat ganggang mikro asal air tawar dan sawah pada skala laboratorium dan lapang: pengaruh konsentrasi hara media
Abstrak: Results of previous studies proved that some types of microalgae have a high growth and high protein content, so it is potential to be cultivated as a source of forage and food substitutes. Protein content is different in each type of micro algae. This research was conducted to determine the optimum composition and concentration of nutrients in the media for cultivating each of the 4 microalgae isolates studied at laboratory scale as well as evaluating their protein content at field scale with 2 days-harvest interval. The study was begun with the cultivation of 4 microalgae isolates (ICBB 9111, ICBB 9112, ICBB 9113, and ICBB 9114) at a laboratory scale each in 50 ml of media with 5 different concentrations. Concentrations of the 5 media tested were: 0.75 times the M4 standard media composition (0.75 M4), M4, 1.25 M4, 1.50 M4, and 1.75 M4. Composition of the M4 standard media used was (g/L): 1.5 NaNO3, 0.049 K2HPO4, 0.0366 MgSO4, 0.0271 CaCl2, 0006 Citric Acid, 0006 Fe-Ammonium Citrate, 0.001 EDTA, 0.02 Na2CO3, and 1 ml micro nutrient with a composition of (g/L): 2.86 H3BO3, 0.1485 MnCl2, 0.1245 ZnSO4, 0.0506 Na2MoO4.2H2O, 0056 CoCl2.6H2O and 0.043 CuSO4. The results of this study indicated that the optimum growth rate at laboratory-scale of the 4 microalgae isolates studied was achieved at different media concentrations: for ICBB 9111 and ICBB 9113 isolates was at the M4 standart media, whereas for isolates ICBB 9112 and ICBB 9114 was at 0.75 M4. These optimum media concentrations were then used for cultivating each isolate at the field scale. Cultivation of the 4 microalgae isolates investigated at the field scale with an harvest-interval of 2 days produced different biomass weight. The average dry biomass production of isolates ICBB 9111, ICBB 9112, ICBB 9113 and ICBB 9114 were, respectively, 0.28, 0.21, 0.26 and 0.32 g/L. These dry biomass were then used to analyze the protein content. The highest protein content was obtained from the isolate ICBB 9114 with an average level of 33.99%, while the lowest one was from the isolate ICBB 9113 with an average level of 26.05%. Variations in biomass and protein production indicated the effects of isolate types of microalgae, rate of nutrients utilization or metabolism and environmental factors.
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Judul: Carbohydrate, protein and lipid production of microalgae in a raceway pond system: use of fertilizer combinations of ZA-NaNO3 and SP36-K2HPO4as N and P nutrient source
Abstrak: Microalgae is a photosyinthetic unicellular microbe which able to convert sunlight, water, carbon dioxide and nutrients to biomass. Since its biomass contains high grade of carbohydrate and lipid, microalgae is a potential source of biofuel. The objectives of this research were to identify 4 selected microalgae strains, to determine the optimum combination of technical grade ZA-NaNO 3 and SP36-K2HPO4 as the N and P nutrient source for cultivation of the strains at laboratory scale, and to evaluate the effects of the optimum combination of the N and P nutrient source on carbohydrate, protein and lipid production of each strain at field scale in a raceway pond system. The results showed that microalgae ICBB 9111 strain is Synechococcus sp., while ICBB 9112, ICBB 9113, and ICBB 9114 are Chlamydomonas sp. The highest carbohydrate was produced by Synechococcus sp. ICBB 9111 (43.90 % dry weight, DW) at 50 % ZA, 50 % NaNO3 and 100 % SP36, 0% K2HPO4 treatment. The highest protein was produced by Chlamydomonas sp. ICBB 9114 (29.09 % DW) at 50 % ZA, 50 % NaNO3 and 100 % SP36, 0 % K2HPO4 treatment. The highest lipid was produced by Chlamydomonas sp. ICBB 9113 (32 % DW) at 50 % ZA, 50% NaNO3 and 50 % SP36, 50% K2HPO4treatment.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf