Judul: Distribusi Cahaya Di Rutan Karet Muara Kuamang Jambi
Abstrak: Distribusi cahaya mcrupakall faktor penting bagi vcgctasi, khuslisnya yang lUl11buh di bawah kanopi hutan. Distribusi cahaya sangat bervariasidi bawah kallopi hulan dan dipcllgaruhi oleh struktur. orientasi dan bentuk kanopi.Secara visual, kOlldisi tersebut dnput dinyatakan sebagai bukaan kanopi yailll bagian langit yang nampak dari suatu titik pengamatan tertentu. Dcngall Illcllgelahui bukaall kanopi dapal diduga potcnsi cahaya yang diterima di bawah kanopi !lutan. Dalam penelitian ini, pendugaan bukan kanopi dan distribusi spasialnya Illcnggunakan Hemispherical Photographs (Hemiphot), model inlersepsi cahaya sederhana (Model SLIM) dan Moose-Horn. Ketiga metode tersebut diuji pada plot permanen hutan karet seluas I ha dan dibandingkan dcngan hasil pengukuran sensor kuantum.
Keyword: 

Judul: Pengembangan sistem berorientasi obyek pada model penyerapan cahaya oleh pohon
Abstrak: Pengukuran intensitas cahaya dalam suatu sistem hutan dapat dilakukan dalam berbagai cara, diantaranya dengan menggunakan alat sensor cahaya atau dengan Hemispherical photographs (hemiphots). Sensor cahaya dengan daya sensitifitas yang cukup tinggi tidak dapat menghasilkan kondisi cahaya rata-rata untuk waktu yang cukup lama. Pengukuran dengan hemiphots menghasilkan ukuran kondisi cahaya yang cukup memuaskan, namun pengukuran tersebut hanya dapat dilakukan pada bukaan tajuk di titik tertentu pada suatu area hutan. Sistem model penyerapan cahaya Simple Light Interception Model (SLIM) dikembangkan untuk dapat menguku nilai intensitas cahaya di berbagai titik pada suatu plot hutan. Sistem ini dibentuk dari pemodelan berbagai obyek dalam suatu sistem hutan. Metode pengembangan berorientasi obyek digunakan untuk pengembangan sistem ini. Penggunaan metode ini sangat sesuai mengingat kemiripannya dengan sistem dalam keadaan nyata. SLIM yang dikembangkan dengan bahasa pemrograman JAVA dapat menghasilkan pemetaan sebaran cahaya yang menunjukan kesesuaian dengan pemetaan posisi pohon dalam suatu plot model hutan. Pemodelan tiga dimensi obyek pohon dengan bentuk ellipsoid dan teknik pengukuran cahaya mengikuti teknik hemiphots menghasilkan rata-rata pengukuran yang cukup mendekati hasil pengukuran herniphots.
Keyword: 

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