Judul: Perbandingan Unit Contoh Lingkaran dan Unit Contoh N-Jumlah Pohon dalam Pendugaan Simpanan Karbon
Abstrak: Penerapan metode penarikan contoh dalam kegiatan inventarisasi hutan pada umumnya menggunakan unit contoh lingkaran, terutama pada tegakan muda hutan tanaman. Selain unit contoh lingkaran, sebenarnya telah diketahui unit contoh berupa n-jumlah pohon untuk pendugaan volume tegakan pada hutan tanaman. Penelitian ini bertujuan membandingkan hasil pendugaan simpanan karbon terhadap unit contoh lingkaran dan unit contoh n-jumlah pohon. Penelitian dilakukan dengan 82 unit tegakan pinus dan agathis berumur 1–5 tahun di areal rehabilitasi TOSO, Hutan Pendidikan Gunung Walat, Sukabumi. Unit contoh 4, 5, dan 6-jumlah pohon ditempatkan pada titik pusat unit contoh lingkaran. Pengukuran dilakukan untuk mendapatkan data diameter dan jarak pohon dari titik pusat. Hasil penelitian menunjukkan unit contoh lingkaran memiliki nilai kesalahan penarikan contoh terkecil dibandingkan unit contoh 4, 5, dan 6-jumlah pohon dalam menduga nilai simpanan karbon sebesar 26.32%. Dengan demikian, unit contoh n-jumlah pohon belum dapat menjadi alternatif unit contoh dalam pendugaan simpanan karbon di areal rehabilitasi TOSO.
Keyword: penarikan contoh sistematik, unit contoh lingkaran, unit contoh n-jumlah pohon, simpanan karbon, tegakan muda

Judul: Perbandingan Unit Contoh Lingkaran dan Unit Contoh Jumlah Pohon dalam Pendugaan Cadangan Karbon Areal Rehabilitasi di Hutan Pendidikan Gunung Walat.
Abstrak: Penerapan sampling pada kegiatan inventarisasi hutan tanaman dapat menggunakan unit contoh lingkaran dan jumlah pohon. Namun, unit contoh jumlah pohon masih jarang digunakan meskipun praktis dan mudah diterapkan. Penelitian ini bertujuan membandingkan unit contoh lingkaran dan unit contoh jumlah pohon serta menduga potensi cadangan karbon yang ada di areal rehabilitasi Hutan Pendidikan Gunung Walat (HPGW). Unit contoh jumlah pohon yang digunakan yaitu sebanyak 6, 8, dan 10 jumlah pohon. Jumlah unit contoh yang digunakan sebanyak 116 plot yang tersebar secara merata di seluruh areal rehabilitasi TOSO dan ConocoPhillips HPGW. Metode sampling yang digunakan yaitu stratified systematic plot sampling with random start. Berdasarkan hasil perhitungan pendugaan cadangan karbon dari unit contoh lingkaran dan unit contoh jumlah pohon diketahui bahwa unit contoh 6 jumlah pohon dapat digunakan untuk menduga cadangan karbon pada areal rehabilitasi HPGW dan memberikan ketelitian yang lebih baik daripada unit contoh lingkaran. Jumlah cadangan karbon di areal rehabilitasi HPGW pada tahun 2017 di blok TOSO sebesar 69.85 ± 16 ton, dan blok ConocoPhillips sebesar 44.89 ± 14.2 ton.
Keyword: cadangan karbon, unit contoh jumlah pohon, unit contoh lingkaran

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