Beberapa Gen pada Bakteri yang Bertanggung Jawab terhadap Produksi Bioetanol

Harga minyak mentah dunia yang berfluktuasi dan cadangan minyak yang makin menipis telah mendorongpenggunaan biofuel sebagai bahan bakar alternatif dan mengintensifkan penelitian bioetanol dengan menggunakanmikroba. Identifikasi dan karakterisasi gen-gen yang bertanggung jawab dalam produksi bioetanol (etanologen) danekspresinya pada beberapa inang telah dilakukan untuk meningkatkan produksi bioetanol oleh mikroba. Tulisan inimengulas sumber-sumber gen bioetanol (pdc dan adh) dan ekspresinya pada beberapa bakteri inang sebagai genyang berdiri sendiri maupun sebagai operon dalam memproduksi bioetanol. Piruvat dekarboksilase (pdc) danalkohol dehidrogenase (adh) adalah gen-gen yang bertanggung jawab dalam produksi bioetanol yang ditemukanpada bakteri mesofilik Zymomonas mobilis dan ragi Saccharomyces cerevisiae. Sumber gen pdc lebih terbatasdibandingkan dengan gen adh. Gen pdc belum ditemukan dalam jaringan hewan maupun bakteri termofilik.Manipulasi genetik beberapa bakteri dengan pdc dan adh yang diisolasi dari beberapa bakteri telah dilakukan untukmeningkatkan produksi bioetanol dari sumber karbon yang murah, yaitu biomassa. Ekspresi etanologen telahberhasil dilakukan pada bakteri mesofilik, baik gram-positif maupun gram-negatif. Namun, ekspresi etanologenpada bakteri termofilik perlu penelitian lebih lanjut untuk mencapai keberhasilan yang tinggi

Pertumbuhan Padi Varietas Ciherang Setelah Diinokulasi dengan Azospirillum Mutan Multifungsi

Modern agriculture is very closely related to the application of fertilizer to induce plants grow. The application of bio-fertilizers is expected to reduce the negative impact of chemical fertilizers. The purpose of this study was to determine the effect of multi-functional Azospirillum N2 fixation, P solubility and IAA production on the growth of Ciherang rice in pot experiment in greenhouse BB Biogen. The experiment treatment were 3 types of inoculation (non-inoculation, inoculation using wildtype Aj Bandung 6.4.1.2 and the mutant isolate of AJM 3.7.1.14 ), and 4 levels of fertilizer application (non-fertilization, a quarter dose, a half dose, and the real dose of fertilization on rice in lowland). The Azospirillum isolates were used wildtype isolate Aj Bandung 6.4.1.2 and mutant isolate AJM 3.7.1.14 that was isolated and mutated using ethyl methanesulfonate (EMS) in BB Biogen. Seeds of Ciherang rice were inoculated using Azospirillum at cell density 106 cell/ml in different seedling tray. After 14 days, the seedlings were transferred to planting pots which consist of 3 plants per pot. Parameters observed were plant height, number of tillers, number of panicles per hill, wet and dry weight of panicles per hill, weight of 100 seeds, N and P content of the stover. The results showed that both wild-Azospirillum and mutant inoculum had no effect on the vegetative growth of Ciherang, but showed significant effect on the number of panicle per hill, grain weight per hill and dry weight of seeds per panicle. The use of Azospirillum and N fertilizer combination affected the growth and rice yields, also reduced chemical fertilizer application

Kinetic Evaluation of Ethanol-tolerant Thermophile Geobacillus Thermoglucosidasius M10exg for Ethanol Production

Thermophiles are challenging to be studied for ethanol production using agricultural waste containing lignocellulosic materials rich in hexose and pentose. These bacteria have many advantages such as utilizing a wide range of substrates, including pentose (C5) and hexose (C6). In ethanol production, it is important to use ethanol tolerant strain capable in converting lignocellulosic hydrolysate. This study was aimed to investigate the growth profile of ethanol-tolerant thermophile Geobacillus thermoglucosidasius M10EXG using a defined growth medium consisted of single carbon glucose (TGTV), xylose (TXTV), and a mixture of glucose and xylose (TGXTV), together with the effect of yeast extract additionto the media. The experiments were conducted at the School of Biotechnology and Biomolecular Sciences of The University of New South Wales, Australia on a shake flask fermentation at 60°C in duplicate experiment. Cultures were sampled every two hours and analised for their kinetic parameters including the maximum specific growth rate (µmax), biomass yield (Yx/s), ethanol and by-product yields (acetate and L-lactate) (Yp/s), and the doubling time (Td). Results showed that this strain was capable of growing on minimal medium containing glucose or xylose as a single carbon source. This strain utilized glucose and xylose simultaneously (co-fermentation), although there was glucose repression of xylose at relatively low glucose concentration (0.5% w/v), particularly when yeast extract (0.2% w/v) was added to the medium. The highest biomass yield was obtained at 0.5 g l-1 on glucose medium; the yield increased when yeast extract was added (at 0.59 g l-1). The highest specific growth rate of 0.25 was obtained in the phase I growth when the strain was grown on a mixture of glucose and xylose (0.5% : 0.5% w/v) medium. Diauxic growth was shown on the mixture of glucose, xylose, and yeast extract. The strain produced low level of ethanol (0.1 g l-1), as well as low level (0.2 g l-1) of by-products (L-lactate and acetate) after 15 hours. The results suggests its potential application for fermenting lignocellulosic agricultural wastes for ethanol production

Agrobacterium Tumefaciens-mediated In-planta Transformation of Indonesian Maize Using Pig121hm-cs Plasmid Containing Nptii and Hpt Genes

Maize (Zea mays L.) productivity in Indonesia is challenged to be increased using genetic engineering. Recent advances in Agrobacterium tumefaciens-mediated in-planta transforma-tion makes it possible to transform maize with low cost, and simple method. This study aimed to confirm pIG121Hm-Cs plasmid in A. tumefaciens, and to estimate the efficiency level of A. tumefaciens-mediated in-planta transformation of Indonesian maize by using pIG121Hm-Cs plasmid containing nptII and hpt genes. A series of studies were conducted including confirmation of gene construct of pIG121Hm-Cs plasmid in A. tumefaciens, transformation of four maize lines through A. tumefaciens-mediated in-planta technique, acclimatization of transformant plants and molecular analysis of selected plants using polymerase chain reaction (PCR). The pIG121Hm-Cs plasmid was confirmed via PCR analysis using specific primers of nptII and hpt genes and resulted 700 bp and 500 bp for fragments of nptII and hpt, respectively. After selection, acclimatization and molecular analysis steps, the efficiency levels of transformation of four maize lines were low, ranging from 3.8% to 12.8%. The level of transformation efficiency of ST-27 line was the highest accounting for 12.8% of 45 planted embryos on selection medium based on PCR analysis using specific primer for nptII gene. Overall, A. tumefaciens-mediated in planta transformation on maize floral pistil in this study proved to be successful and rapid. Therefore, this enhanced transformation method will be beneficial for Indonesian maize genetic engineering

Pembentukan Populasi Mutan Azospirillum Dengan Menggunakan Transposon Untuk Sifat Superior Terhadap Pelarutan P

Azospirillum sp. which has the ability for nitrogenfixation and phosphate solubilization may support modernfarming in Indonesia that is mostly dependent on the USAgeof chemical fertilizer N, P, and K. Genetic quality ofAzospirillum was improved in this research to obtainsuperior characters toward phosphate solubilization so thatit can become more effective in use for farmers. To achievethis goal, Azospirillum was mutated by means ofelectroporation using transposon EZ-Tn5<kan-2>Tnp. Theelectrotransformation resulted in 20 out of 22 transformantstested contained the marker gen (npt). 10, 6 and 4 mutantshave increased, decreased and lost phosphate-solubilizingfunction, respectively. Mutant with elevated phosphatesolubilizingability may be selected further to be utilized asbiofertilizer while others may be useful for identification ofgenes responsible for phosphate solubilization

Penentuan Alergenisitas Protein Gen RB Pada Kentang Produk Rekayasa Genetika Berdasarkan Studi Bioinformatika

Genetically modified products (GMP) of Katahdin potato event SP951 containing RB gene resistant to late blight diseasescaused by Phytophtora infestans has been developed in the USA. This Katahdin SP951 potato has been crossed with localvarieties Atlantic and Granola for its development in Indonesia. In the release process, the GMP potato should be tested forenvironmental and food safety. One of the food safety assessment needs to be done by determining allergenicity of RB proteinwhether it is potential as allergen. This research aims to translate the RB gene sequence into RB protein sequence andinvestigate the potential RB protein as an allergen through bioinformatic studies. This study was performed based on thealignment with available protein allergens from available database websites. The predicted RB protein obtained from 2,913amino acids RB gene was a 971 amino acids length protein with ATG as a start codon and TAA as a stop codon. Bioinformaticsstudies of RB protein were performed using www.allergenonline.com, consisted of three searches, i.e. full-length search byFASTA, 80 amino acids search by FASTA, and 8 amino acid exact matches. For full-length alignment search, there are threeallergen proteins similar with RB protein sequence with the percentage identity of <35%, while for alignment with 80 aminoacids and 8 amino acids did not show similarity with any allergen protein in the database. It can be concluded that RB proteindid not have any potential as an allergen, as according to Codex Alimentarius guidelines for full-length alignment search, onlyprotein with identity greater than >50% indicating possible cross reactivity with protein allergen

Pembentukan Populasi Mutan Azospirillum dengan Menggunakan Transposon untuk Sifat Superior terhadap Pelarutan P

Azospirillum sp. which has the ability for nitrogenfixation and phosphate solubilization may support modernfarming in Indonesia that is mostly dependent on the usageof chemical fertilizer N, P, and K. Genetic quality ofAzospirillum was improved in this research to obtainsuperior characters toward phosphate solubilization so thatit can become more effective in use for farmers. To achievethis goal, Azospirillum was mutated by means ofelectroporation using transposon EZ-Tn5<kan-2>Tnp. Theelectrotransformation resulted in 20 out of 22 transformantstested contained the marker gen (npt). 10, 6 and 4 mutantshave increased, decreased and lost phosphate-solubilizingfunction, respectively. Mutant with elevated phosphatesolubilizingability may be selected further to be utilized asbiofertilizer while others may be useful for identification ofgenes responsible for phosphate solubilization