Judul: Pembuatan Prebiotik Manooligosakarida (MOS) serta pengujiaanya Terhadap Pertumbuhan Salmonella sp. dan Pediococcus pentosaceus
Abstrak: Prebiotic was recomended as a substitute for antibiotics in the feed ingredients. One of prebiotics is mannooligosaccharide (MOS). MOS is the result of bacterial degradation from mannose containing substrates. The aim of this research is to analyze the ability of the W6 to produce mannooligosaccharide prebiotics from palm kernel cake (PKC) and test it against the growth of lactic acid and pathogenic bacteria. The analyses were performed with the clearing zone test, enzyme activity, substrate concentration election of palm kernel cake (PKC), and the growth of lactic acid and pathogenic bacteria tests. Isolate W6 had mannanolytic index of 6.5. The results of the clearing zone showed a transparant red color. Isolate W6 had several peaks of enzyme activity, at 24th, 30th , 48th , 78th , and 96th hours of culture incubation. Highest mannanase activity of isolate W6 at pH 5.5 and 30° C with incubation time of 96 hours was 0.0265 U/mL. The isolate was able to produce the best MOS with PKC concentration was 10%. The prebiotic MOS increase the growth of Pediococcus pentosaceus and was able to inhibit growth of Salmonella sp. It is concluded that W6 has the degree of polymerization at 3.3-8.6 in production of MOS as prebiotic.
Keyword: Bogor Agricultural University (IPB), prebiotic, mannooligosaccharide, mannanolytic, palm kernel cake

Judul: Isolasi dan Pencirian Bakteri Mananolitik Pendegradasi Bungkil Inti Sawit
Abstrak: Mannanase is an enzyme which can be utilized in food and feed sector. This research is aimed to isolate and characterize the mannanase producing soil bacteria from palm plantations in Cikasungka, Bogor, and to know the ability of manannase in hydrolyzing palm kernel cake (PKC) substrate become to manno-oligosaccharide (MOS). There were 8 isolates isolated from the soil of Cikasungka Plantation, Bogor. Three isolates were choosen with the highest mannanolytic index to be further characterized. Isolate 5 produced the highest mannanase activity at 18 h of incubation (0.039 U/mL) and 54 h (0.051 U/mL). Isolate 6 produced the highest mannanase activity at 30 h of incubation (0.041 U/mL) and 66 h (0.058 U/mL). Isolate 7 produced the highest mannanase activity at 24 h of incubation (0.041 U/mL). The specific activity of isolate 5, 6 and 7 had value 2-3 times higher than their own enzymatic activity. One selected isolate, isolate 6 had optimum activity in pH 5.5 at 30 °C and pH 7 at 40 °C. The enzyme stability of isolate 6 were decreasing at the both pH and temperature optimum. The polimerization degree of isolate 6 in pH 5.5 at 30 °C had value of 4.0-4.1 and 6.9-7.5 in pH 7 at 40 °C. Isolate 6 posseses high degree of polimerization in MOS production, it is potentially used as cattle prebiotic.
Keyword: mannanase, mannanolytic, manno-oligosaccharide, palm kernel cake, polimerization degree

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