Judul: Pereduksian Matriks Komposisi Tegakan Hutan dengan Analisis Komponen Utama dan Diskriminan Kanonik
Abstrak: Penelitian ini bertujuan untuk meneliti pengaruh data bergrup dan hadirnya pencilan dalam menjelaskan hasil pereduksian dimensi dengan Analisis Komponen Utama (AKU) yang diluar harapan. Matriks data diidentifikasi begrup berdasarkan informasi yang diperoleh belakangan tentang adanya keanekaan dalam faktor-faktor sistem lahan, altitude dan kelerengan medan dalam suatu kawasan luas yang mencirikan habitat petak contoh. Analisis Ragam Peubah ganda diterapkan untuk melacak determinasi keragaman habitat-habitat terhadap keragaman komposisi-komposisi s spesies.
Keyword: 

Judul: Pembedaan kelas umur dan tinggi tegakan pinus merkusii jungh et de vries melalui foto udara dengan pendekatan analisis diskriminan di KPH Bandung Utara Perum Perhutani Unit III Jawa Barat
Abstrak: Pengelolaan hutan di Indonesia telah berlangsung puluhan tahun. Berbagai penelitian untuk meningkatkan kinerja telah banyak dilakukan. Hasil-hasil penelitian tersebut antara lain metoda-metoda pengelolaan dan teknik-teknik silvikultur serta tabel-tabel tegakan. Tabel-tabel tegakan yang selama ini dikenal dan telah baku adalah tabel tegakan terestris, sedangkan tabel tegakan udara masih belum banyak dikenal. Peubah-peubah foto udara yang berperan nyata dalam tabel tegakan udara masih diteliti. Penelitian tersebut dilakukan antara lain dengan pengamatan terhadap pembedaan kelas umur dan tinggi. Pinus merkusii Jungh et de Vriese yang dikenal sebagai tusam atau pinus adalah jenis cepat tumbuh penyuplai bahan baku pulp, selain itu juga menghasilkan getah yang dijadikan bahan baku terpentin dan gondorukem. Tegakan Pinus merkusii di Perum Perhutani berbentuk sebagai hutan tanaman yang dibagi-bagi dalam 8 kelas umur dengan interval 5 tahun. Tujuan penelitian ini adalah mengetahui sejauh mana kelas umur dan tinggi dapat dibedakan melalui foto udara dengan pendekatan analisis diskriminan serta mengetahui peubah apa saja yang berperan nyata dalam membedakan suatu kelas umur dan tinggi. Data yang digunakan berasal dari Proyek Kerjasama Perum Perhutani dengan Fakultas Kehutanan IPB dalam pembuatan Kunci Interpretasi dan Stereogram di KPH Bandung Utara, pada bulan Februari 1998. Selanjutnya pengolahan dan analisis data berlangsung dalam bulan Mei-Juni 1998
Keyword: pinus

Judul: Extracellular Expression of thermostable Geobacillus stearothermophilus T1.2RQ Lipase for Biodiesel Production
Abstrak: The extracellular expression of enzymes in an excellent secretion host such as Bacillus subtilis is a useful strategy for making enzymes of industrial significance more affordable by lowering the cost of its downstream processing. Lipases are a category of hydrolases that catalyze the hydrolysis of triglycerides to glycerol and free fatty acids. Also, lipases catalyze the hydrolysis and transesterification of other esters as well as the synthesis of esters. They can perform very specific biotransformation reactions and are widely used in food, organic synthesis, detergents, cosmetic, and pharmaceutical industries. Geobacillus stearothermophilus T1.2RQ lipase is an industrially-desired thermostable lipolytic enzyme with an excellent hydrolytic and transesterification activity. This study aimed to express T1.2RQ lipase, in B. subtilis WB800 and ensure its secretion into the extracellular medium. Three signal peptides (AmyQ, Epr, LipA) and two promoters (Pgrac01 and Pgrac100) were used in the secretory-expression of T1.2RQ lipase, based on five constructed expression vectors constructed by restriction cloning and PCR mutagenesis. Sangers sequencing was used to verify constructs to ensure they are in the correct reading frame. Recombinants vectors, pHT43 (plasmid control), pHT43-T1.2RQ, pHT43- T1.2RQ_AmyQ, pHT43-T1.2RQ_Epr, and pHT43-T1.2RQ_LipA, were transformed by electroporation into Bacillus subtilis WB800. The electroporation was successful with the optimum condition of 2500V, 200 ohms, 25µF, and 5milliseconds. Recombinant B. subtilis pHT43 (negative control) and pHT43-T1.2RQlip + signal peptides were streaked on the lipidic agar, LA+TBN. All four recombinants, including the negative control (B. subtilis WB800-pHT43), produced clear zones on the TBN agar plate after overnight incubation (fig 2), indicating the presence of a lipolytic enzyme in all of the recombinant B. subtilis cells. pHT43-T1.2RQlip + signal peptides (AmyQ, Epr, and LipA) have clear zones with significantly higher diameters than B. subtilis WB800-pHT43 (negative control). This phenomenon suggests that the recombinant thermostable lipase T1.2RQ introduced into these cells was successfully expressed, thereby increasing the lipolytic capability of its host cells T1.2RQ lipase was expressed in 50ml terrific broth medium (TB) and the expression induced with 1mM IPTG. Lipase activity assay using p-nitrophenyl esters showed that all three signal peptides directed the secretion of T1.2RQ lipase into the extracellular medium. Signal peptide, LipA, resulted in the highest extracellular activity of 5.6 U/mL, which corresponds to a 6-fold increase over the parent B. subtilis WB800 strain. Meanwhile, signal peptides, AmyQ and Epr produced 4.2 U/mL and 3.4 U/mL activity respectively. SDS-Zymogram analysis confirmed that T1.2RQ lipase was correctly processed and secreted in its original size of 44 kDa. An attempt to further increase lipase expression level by promoter optimization showed that, contrary to expectation, promoter Pgrac100 exhibited similar expression levels as the original Pgrac01. Nevertheless, the demonstration of the successful secretion of T1.2RQ lipase in this work confirms the latter as a promising approach for the industrial production of the enzyme
Keyword: Bacillus subtilis, Expression, Extracellular, Heterologous, Lipase, Thermostable