Judul: Collagenase of Bacillus licheniformis F11 from Palembang and application to produce bioactive collagen peptide
Abstrak: Collagenase is endopeptidase which can cleave helical collagen into small peptide fragments. The objective of the study was to select Bacillus licheniformis F11 which produced the best collagenase, purify collagenase dan characterize the crude and purified collagenase and apply collagenase from Indonesian Bacillus licheniformis in the production of bioactive collagen peptides which act as antioxidant, inhibitor of ACE (angiotensin I-converting enzyme) and anti cancer. The Bacillus licheniformis F11.1 and F11.4 were deleted gen from B. licheniformis F11, respectively. Collagenase from B. licheniformis was selected for application to hydrolyze fish skin collagen to produce collagen peptides. B. licheniformis 11.1 produced higher protease activity as compared to B. licheniformis F11.4 when grown in LB media. The optimum production time was 15 h for B. licheniiformis F11.1 with protease activity of 0.028 U/ml or 0.909 U/mg protein. For B. licheniformis F11.4 it was between 20-35 hours of fermentation, with enzyme activity of 0.005 U/ml or 0.157 U/mg protein. When collagen was added to the Modified LB media different responses were obtained. The activity of protease from B. licheniformis F11.1 decreased from 0.028 U/ml or 0.909 U/mg protein to 0.005 U/ml or 0.172 U/mg protein while that of B. licheniformis F11.4 increased from 0.005 U/ml or 0.157 U/mg protein to 0.017 U/ml or 0.546 U/mg protein. Based on result from extracellular collagenase production and spesificities towards substrate and finger print substrate, B. licheniformis F11.4 was selected for further study. Enzyme purification was done with ammonium sulphate 50% (w/v) precipitation, followed by DEAE Sephadex A-50 column chromatography. Precipitation with ammonium sulphate resulted in 5-fold purification with a yield of 10.1%. After purification with DEAE Sephadex A-50 column, the enzyme was purified 26.3-fold with a yield of 2.6%. The relative molecular weight was estimated to be 124 and 26 kDa. The optimum activity of both crude and purified collagenase (without and with Ca2+) were observed at 500C. The crude enzyme had pH optimum at 9.0, while the purified enzyme at 7.0. The crude collagenase activity was inhibited by FeCl2 (1mM) and CoCl2 (1 mM) while CuCl2 increased its activity. The purified collagenase activity was inhibited by CuCl2 (1 mM), FeCl2 (1 mM), MgCl2 (1 mM) and CoCl2 (1 mM). However, CaCl2 (10 mM), ZnCl2 (5 and 10 mM) and CuCl2 (5 and 10 mM) increased its activity. The radical scavenging activity (as measured by DPPH) of the collagen peptide hydrolysed with purified collagenase was higher (30.28%) than that of these hydrolysed with crude collagenase (23.50%). However, ferric ion reduction activity of the collagen peptide hydrolysed with crude collagenase (2.12) was higher than that of the collagen peptide hydrolysed with purified collagenase (0.78) and these were also higher than the 2.0 mM BHT antioxidant used as control. The ACE (Angiotensin I-Converting Enzyme) inhibitor activity of the collagen peptide hydrolysed with crude was higher (83%) as compared to that hydrolysed with purified collagenase (74%). The antiproliferation activity towards HeLa cervix cancer cells of the collagen peptide hydrolysed with purified collagenase (39.2%) was higher than that of the collagen peptide hydrolysed with crude (23.5%). The antiproliferation activity towards HCT-116 colon cancer
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Judul: Produksi Kolagenase dari Isolat Bacillus licheniformis F-11.1 dan F-11.4
Abstrak: Hydrolysis by collagenase enzyme could increase nutrition and function of food proteins. This research was conducted to produce collagenase enzyme from Bacillus licheniformis F-11.1 and F- 11.4. B. licheniformis isolate F-11.1 and F-11.4 were cultured in three types of production media, which is Luria Bertani (LB) media consisted of 5% collagen (LBC), 50% LB media consisted of 5% collagen (LBHC), and 5% collagen (CLG). The activity of collagenase, protein content, and cell turbidity of B. licheniformis F-11.1 and F-11.4 were measured every 5 hours during 50 hours incubation. The result showed that optimum collagenase production of B. licheniformis isolate F- 11.1 was reached in LBC and LBHC media with activity of 2,057 U/mg and 2,037 U/mg, respectively. Optimum collagenase production of B. licheniformis isolate F-11.4 was reached in LBC media with activity of 4,695 U/mg. Isolate F-11.4 in LBHC media possesed the optimum collagenase activity of 2,811 U/mg. CLG media gave optimum collagenase activity of B. licheniformis F-11.1 and F-11.4 at 0,807 U/mg and 0,306 U/mg respectively. These research concluded that LBC and LBHC media was the best choice for collagenase production of B. licheniformis F-11.1 and F-11.4.
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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