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.
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Judul: Pendugaan Lengas Tanah dan Indeks Luas Dann dengan Data Satelit NOAA-A VHRR di Rutan Tropika Basah; Studi Kasus di Muarabungo, Jambi
Abstrak: Lengas tanah dan intensitas radiasi surya merupakan unsur iklim yang sangat mempengaruhi kondisi lingkungan hutan tropika dataran rendah sehingga sangat penting dipelajari melalui penelitian ini. Namun demikian, aspek wilayah yang luas juga diperhitungkan karena menjadi kendala pengamatan sehingga diperlukan altematif penggunaan satelit sebagai alat pemantau. Penelitian ini bertujuan untuk mempelajari faktor-faktor yang mempengaruhi distribusi dan perubahan nilai potensial lengas tanah pada tiga tipe hutan yaitu hutan primer, hutan bekas tebangan, dan hutan sekunder. Selanjutnya mencari hubungan antara potensial lengas tanah ditiga tipe hutan tersebut dengan data NOAA-A VHRR sebagai upaya memantau kondisi lingkungan hutan tropika basah dalam skala spasial yang luas dengan cepat. Penelitian ini juga bertujuan untuk melakukan pendugaan nilai indeks luas daun (ILD) melalui pendekatan alometris, kemudian digabungkan dengan pendekatan optis untuk memperoleh nilai koefisien penyirnaan (k). Diharapkan nilai k ini dapat dijadikan patokan untuk menduga nilai ILD melalui pendekatan optis di hutan primer dan hutan bekas tebangan di Pasirmayang, Jambi. Hasil penelitian ini menunjukkan bahwa potensial lengas tanah di hutan sekunder lebih peka terhadap pengaruh lingkungan daripada hutan primer dan hutan bekas tebangan, terutama pada musim kemarau (Juni-Agustus 1994). Faktor-faktor lingkungan yang sangat berperan dalam ketersediaan Jengas tanah adalah curah hujan, keterbukaan kanopi, dan sifat fisik tanab, sedangkan fluktuasinya yang dinyatakan dengan potensial air tanah (\j/, k:Pa) sangat dipengaruhi oleh curah hujan. dst ...
Keyword: NOAA-AVHRR;

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