Judul: Biochemical and Microbial Changes during Palm Kernel Meal (PKM) Fermentation
Abstrak: Fermentation was the first step of bioconversion process of palm kernel meal (PKM). The fermentation was done in close canister to minimize the environmental effect. The study was conducted to investigate total microorganism and biochemical changes during PKM fermentation in a closed canister. Fourty two kg of PKM were mixed with 84 L of water and put in the big drum (height 81 cm; diameter 48 cm). The fermentation height in drum is 80 cm. The sample was taken in the depth of ±40 cm from the surface. At interval 12 hours during 7 days take a sample for microbial analysis, pH, total acid, temperature, fibre, protein content, D-mannose, and volatile organic acid. The highest number of aerobic bacteria, 17.2 log10 CFU/g, was found at 24 hours of fermentation PKM. The highest total anaerobic bacteria, 17.3 log10 CFU/g, were found at 72 hours of fermentation PKM. No fungi was found before 96 hours of fermentation and the highest number found, 6.4 log10 CFU/g, was at the end of fermentation PKM. The pH of fermentation decreased after 48 hours from 4.56 to 4.28. The decreased of pH followed by increased total acid concentration from 0.19 to 0.22 mMol/mL after 48 hours of fermentation PKM. After 168 hours of fermentation PKM, the protein content increased 4.79%; while the concentration of hemicellulose, cellulose, and lignin decreased 10.79%, 10.77%, and 51.34%, respectively. The highest mannose concentration, 3.297±0.13 g/L, was found after 36 hours of fermentation PKM. The dominant volatile organic acid is acetic acid with a concentration of 87.89 mMol after 72 hours of fermentation PKM.
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Judul: The reduction of contaminant compounds of palm oil mill effluent by two phase anaerobic fermentation using two-stage anaerobic digester
Abstrak: Palm oil is one of the potential comodities in Indonesia. Production of crude palm oil (CPO) will produce solid, liquid, and gas waste. Wastewater from palm-oil plant which also known as palm oil mill effluent (POME) has very high contaminant charge. It can contaminate environment if it is directly loosed away. This research aimed to investigate the mixture of POME and activator ratio with palm oil contaminant charge decreasing considered from BOD, COD, and TSS value by anaerobic processing during 40 days. This research was done at Animal Science Laboratory, Bogor Agricurtural University. Raw material used in this research was POME and activator. Activator is mixture of biogas sluge and cattle beef feces (20:80). Equipment used in this research was two stage anaerobic digester. The treatment were ratio of POME and activator 70%:30% (P70S30), 80%:20%(P80S20), and 90%:10% (P90S10). The physico-chemical analysis has resulted from the first condition show high value of influent BOD, COD, and TSS. The BOD value of influent P70S30, P80S20, and P90S10 consecutively are 8871 mg/l, 8871 mg/l, and 6653 mg/l. The COD value of influent P70S30, P80S20, and P90S10 consecutively are 15480 mg/l, 17028 mg/l, and 13588 mg/l. The TSS of influent P70S30, P80S20, and P90S10 consecutively are 17010 mg/l, 23250 mg/l and 6530 mg/l. The result of this research showed that the highest decrease of percentage of BOD value was about 80% in first digester which P70S30, followed by P90S10 (69,96% ) and P80S20 (58,99%). The decrease of COD value was about 74% in digester P70S30, followed by P80S20 (73,24%) and P90S10 (67,03%). The decrease of TSS value was about 66% in digester P70S30, 66,60% in digester P80S20 and 61,40% in digester P90S10. The decrease of POME contaminant value was proceed from organic material decomposition by microorganisms in anaerobic biodegradation during 40 days fermentation. Beside on differentiation of contaminant compounds decreasing (digester A and digester B) showed that first digester have higher contaminant compounds reduction than second digester , The best mixture of POME and activator was digester which added 30% activator, followed by digester which added 20% and 10% activator.
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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. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.