Judul: Tetes Tebu sebagai Alternatif Sumber Karbon untuk Produksi Asam Laktat oleh Lactobacillus delbrueckii subsp. bulgaricus
Abstrak: Lactic acid is needed as an industrial feed, especially for applications in the food sector. However, by using a microbial production still uses food material as a substrate. Alternative substrates for the production of lactic acid is needed in industry. Molasses are potential substrates due to the richness in carbon. Molasses also widely available and low-cost material. The objective of the research is molasses can be used as a carbon source needed by Lactobacillus delbrueckii subsp. bulgaricus to produce lactic acid. This study consisted of hydrolysis and detoxification of molasses, analysis qualitative test of reducing sugar from molasses, analysis of total sugar by phenol sulfuric acid, determination of bacterial growth, production and extraction of lactic acid, and analysis of lactic acid using high performance liquid chromatography. The results showed that molasses can be used as an alternative carbon source as indicated by growth of bacteria when the media were given 0.5% molasses. Concentration of total sugar molasses was 1090 g/L. The reducing sugar test showed positive results for the Selliwanoff, Benedict, and Barfoed tests. The optimum of L. delbrueckii subsp. bulgaricus growth was at temperature of 42° C and 150 rpm of agitation. Production of lactic acid was conducted in 24 hours. The result of lactic acid from the production was 2.80%. The dry cell biomass was 0.002 g/ L at pH of fermentation media was 4.0. Analysis HPLC also showed that lactic acid was the product of fermentation
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Judul: Seleksi dan Optimasi Bakteri Asam Laktat Penghasil Senyawa Antikapang
Abstrak: Silage is the forage preservation product through anaerobic fermentation by using lactic acid bacteria (LAB). The presence of oxygen may activate the other microbe that could be contaminate and interrupt the silage processing. Fungi is a microbe that often contaminate silage processing. In Indonesia, prevention of silage contamination by fungi is necessary in order to support livestock business. By using the inoculum that able to produce antifungal compounds, the fungi contamination could be prevented. This research was dedicated to screen LAB having antifungal properties, taxonomic study and optimization of antifungal production. Screening of antifungal producing LAB was initiated by growing LAB on de Man Rogosa Sharpe Agar (MRSA) against Aspergillus fumigatus, A. flavus, and Penicillium by plate assay method (aerobic condition) and verified by deep tube technique (anerobic condition). The results showed that strain DR 1-6-2 could inhibit A. fumigatus and A. flavus in aerobic condition with percentage of inhibition was 41% and 32 %, respectively. In anaerobic condition, strain DR 1-6-2 could inhibit not only A. fumigatus, A. flavus, but also Penicillium. Identification of selected LAB was carried out using 16S rRNA gene sequencing with 27F and 1492R primer. Based on molecular analysis, strain DR 1-6-2 is belong to Lactobacillus plantarum with the degree of homology of 98%. Optimization of antifungal production by selected LAB was carried out using Response Surface Method (RSM) with Central Composite Design (CCD) on five variables (glucose, yeast extract, CH3COONa, K2HPO4, Tween 80) and five level combinations. From statistical analysis, the production of antifungal which is represented by the total lactic acid production of selected LAB is significantly influenced by glucose, combination of glucose and K2HPO4, combination of yeast extract and K2HPO4 and Tween 80. The optimum concentration of glucose is 2.91%, yeast extract 0.58%, K2HPO4 0.29% and Tween 80 0.19% with a maximum predicted lactic acid yield of 2.61%, which is increased by 59%. This result is confirmed when the optimum concentration of nutritions used. The production of lactic acid increased by 58%. Benefit of this research is utilization of indegenous LAB isolates as the silage inoculum and antifungi to prevention of contamination and to obtain a good silage quality. This LAB utilization is capable to trigger the silage production, which in turn could increase the silage utilization as animal feed, increasing the production of meat, and could support the government's efforts to achieve the national demand of meat product. In silage fermentation using L. plantarum DR 1-6-2, anaerobic condition is a requirement to be considered. Identification of other antifungal compounds produced by L. plantarum DR1-6-2 is need to be studied.
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Judul: Pengukuran Engagement pada Permainan Orbital-X, Permainan Pertahanan Menara Sirkular
Abstrak: Jenis permainan pertahanan menara (tower defense) adalah sebuah gaya permainan yang memiliki tantangan tersendiri untuk menyusun sebuah strategi melawan musuh dengan menempatkan menara pertahanan yang tepat. Permainan dalam tugas akhir ini adalah permainan pertahanan menara yang memiliki konsep berbeda, yaitu dengan menaruh menara pertahanan di posisi tengah dan menara lainnya berputar sirkula. Sebelum permainan disebarkan, dibuat 2 buah kuesioner, yaitu kuesioner pra-permainan dan pasca permainan untuk mengukur engagement pemain. Kuesioner pra-permainan diberikan kepada 5 orang. Kemudian, mereka diberi waktu untuk memainkan Orbital-X selama satu minggu. Setelah itu, kelima responden diberikan kuesioner pasca permainan untuk mengukur engagement ketika bermain. Hasil pengukuran engagement pada aspek immersion, pemain sangat setuju dengan pertanyaan “Saya dapat dengan mudah menggunakan kontrol Orbital-X dan saya dapat menguasainya dengan cepat” dan pemain sangat tidak setuju dengan pertanyaan “Interaksi yang terjadi dalam dunia game yang saya mainkan sama halnya seperti saya berinteraksi di dunia nyata”.
Keyword: Engagement, Gameplay, Immersion, Permainan, Pertahanan Menara