Judul: Aktivitas Lakase Pleurotus ostreatus pada Pelepah Sawit dan Tandan Kosong Kelapa Sawit sebagai Substrat
Abstrak: Volume of midrib of oil palm and empty fruit bunches of oil palm (EFB) increase every year. This wastes haven’t been used optimumly. Wastes contain lignocellulosic. Pleurotus ostreatus can degradation of lignocellulosic material, because it has ligninolytic enzymes. One of the ligninolytic enzyme is laccase. This research is aimed to know the laccase activity from two strains of P.ostreatus to hydrolisis substrat of midrib and EFB. Isolate P.ostreatus were isolated from SEAMEO Biotrop baglog and Gadok baglog. Laccase activity in midrib media and EFB media which incubated by JTG was better than incubated by JTB. The laccase activity in midrib media which incubated by JTG was 1,024 U/ml at 30 days, and laccase activity increased 2,002 U/ml at 35. The laccase activity in EFB media which incubated by JTG was 1,561 U/ml at 30 days, and there weren’t laccase activity in EFB media which incubated by JTB and JTG at 35 days after incubation. Protein in midrib media which incubated by JTG was 9,009 mg/ml at 30 days, and increased to 11,371 mg/ml at 35 days. Protein in midrib media which incubated by JTG better than protein in midrib media which incubated by JTB. Protein EFB media which incubated by JTG was 14,535 mg/ml at 30 days. The substrate midrib of oil palm and EFB of oil palm colored light brown after incubation 30 days. The tekstur of substrate midrib of oil palm was crumby. The empty fruit bunches of oil palm tekstur was easier to become apart.
Keyword: Bogor Agricultural University (IPB), Empty fruit bunches of oil palm (EFB)., midrib of oil palm, laccase, Pleurotus ostreatus

Judul: Aktivitas Xilanase Beberapa Pleurotus ostreatus Menggunakan Substrat Pelepah dan Tandan Kosong Kelapa Sawit
Abstrak: Xylanase is a unique enzyme which could produced by bacteria and fungi. Xylanase has been known to have a various pH and temperature for its optimum activity, a reason why xylanase could be used in industries. Pleurotus ostreatus is a member of Fungi kingdom. In Indonesia, P. ostreatus known as jamur tiram. Jamur tiram is one of the favorite fungi to be cultured and probably produced xylanase. For many years, people are using sawdust for making fungi’s media culture, but there are a lot of agriculture and estate waste, for example palm oil’s frond and empty fruit bunch (EFB). This research was aimed for selection of P. ostreatus from many places which secreted xylanase by using palm oil’s frond and EFB as a substrat. Isolate BIOTROP and Gadog were fungi which produced xylanase and also celullase and lignolytic enzymes. After 30 days, weight media decrease between 9.17% until 40.69% from weight media before 30 days incubate. There was a different pH in palm oil’s frond and EFB media. The ratio of C : N showed change of carbon and nitrogen content before and after 30 days of incubation. The highest activity of xylanase enzyme was 0.584 IU/mL reached after 37 days of incubation. It was achieved from P. ostreatus Gadog strain using palm oil’s frond as a substrate. The highest protein concentrate was 35.6 mg/mL reached after 42 days of incubation. It was achieved from P.ostraetus Gadog strain using EFB as a substrate.
Keyword: Bogor Agricultural University (IPB), Xylanase., Pleurotus ostreatus, Palm Oil’s Frond, EFB

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