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Abstract. A few thermophilic bacteria were isolated from a hot spring located in Papandayan Crater, Garut. One of the organisms showed a well growth at temperature of up to 80 o C. Chromosomal DNA from the organism was isolated and used to amplify 16S rRNA gene fragment. The gene was amplified by a set of universal primers (27F and 1492R) resulting in a 1.5 kb DNA fragment. The gene was cloned and sequenced. The phylogenetic tree, homological analysis, and detailed comparison of the sequences showed that 16S rRNA gene sequence of the Papandayan isolate is unique compared to other known strains, however the sequence had closest similarities with Bacillus caldolyticus and Bacillus caldotenax.

Genetic diversity of nine marine macroalgae from coastal area of Sayang Heulang were assessed based on phenotypic and ribotyping analysis. Morphology of the macroalgaes were classified based on the color of the organism such as red (4 samples), brown (3 samples) and green (2 samples). Genomic DNA from the organisms were isolated using CTAB method with slight modification. The 18S rRNA gene amplified by PCR method using standar primers for V4 region of 18S rRNA gene. The amplicons were sequenced and analysed. The results showed that all the sequences are closed to V4 region of 18S rRNA gene. Comparison among the nine sequences showed a variation of homology. The best homology was shown by the sequence of SB and TC (99,1%), both are brown color macroalgea. The lowest homology was shown by GU (red color) and TC (brown color) with the homology at around 64,6%. Further analysis by comparing among the same color and the cross color showed that the same color does not show genetically close each other. Phylogenic analysis showed that the three brown colors are closed each other, however the rest are seen different and far away each other.

Heterologous expression and purification of thermostable lipase from Geobacillus thermoleovorans PPD2 had been carried out through Escherichia coli BL21 as host. Two bands obtained showed lipolytic activity with the size at around 51 (LipA) and 43 (LipB) kDa, respectively. The activities were identified by zymogram analysis, while the control protein from Escherichia coli BL21(DE3) do not show any lipolytic activity. Purification of crude extract using chromatography affinity Ni-NTA resulted one dominant band of LipA, meanwhile LipB did not appeared on the gel. Another purification for LipB was carried out by acetone fractionation. Both of LipA and LipB showed high activity toward medium chain length substrates, with optimum activity at 50oC and pH 8.5. The activities of LipA and LipB showed tolerance toward short chain alcohols, such as methanol, ethanol, n-propanol, and isopropanol.

Lipase's thermostability and organic solvent tolerance are two crucial properties that enable it to function as a biocatalyst. This study examined the characteristics of two recombinant thermostable lipases (Lk2, Lk3) based on transesterification activity. Conversion of C12-C18 methyl ester with paranitrophenol was investigated in various organic solvent. Both lipases exhibited activity on difference carbon chain length (C12 – C18, C18:1, C18:2) of substrates. The activity of Lk2 was higher in each of substrate compared to that the Lk3. Experimental findings showed that the best substrates for Lk2 and Lk3 are C18:1 and C18:2 respectively, in agreement with the computational analysis. The activity of both enzymes prefers on nonpolar solvent. On nonpolar solvent the enzymes are able to keep its native folding shown by the value of radius gyration, solvent-enzyme interaction and orientation of triad catalytic residues. Lk3 appeared to be more thermostable, with maximum activity at 55°C. The presence of Fe3+ increased the activity of Lk2 and Lk3. However, the activity of both enzymes were dramatically decreased by the present of Ca2+ despite of the enzymes belong to family I.1 lipase known as calcium dependent enzyme. Molecular analysis on His loop of Lk2 and Lk3 on the present of Ca2+ showed that there were shifting on the orientation of catalytic triad residues. All the data suggest that Lk2 and Lk3 are novel lipase on the family I.1 and both lipase available as a biocatalyst candidate.

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The macroalgae or seaweed is a biological resource of the Indonesian sea which contains the bioactive compounds. The antimicrobial resistance is a main problem This study aim to know the antibacterial activity from the lipid crude extract of Sargassum polycistum in methanol and chloroform phase in inhibiting the growth of Bacillus cereus and Staphylococcus aureus. The lipid extraction used soxhletation with methanol:chloroform solvent combination (1:2/v/v). Antibacterial assay used disc diffusion method according to Kirby-Bauer. The most lipid extraction result is obtained in methanol phase, approximately 11,2% (v/b) while its chloroform phase is only 3,8% (v/b). The chloroform phase has no inhibition zone in Bacillus cereus and Staphylococcus aureus growth while its methanol phase gives antibacterial activity where its clear zone diameter is 14 mm.

Understanding the role of AIF modulate menadione cytotoxicity may lead Apoptosis Inducing Factor (AIF) contribution as potential target of cancer drugs. Previous studies reported the impact of mitochondrial AIF to cytotoxicity of menadione (2-methyl-1,4-naphtoquinone). Specifically, recent study revealed that AIF depletion reduced the level of thiodione (arylation product of menadione and reduced gluthatione, GSH) and increased endogenous GSH. However, how AIF modulate menadione-GSH arylation, has not been elaborated yet. This study investigated the involvement of AIF to arylation capacity of menadione using in silico approach. Molecular interaction between residues on AIF and functional groups of menadione were investigated using AutoDockVina software. The result confirmed that AIF is involved in the conjugation of menadione and GSH to form thiodione. AIF also tends to stabilize thiodione formation rather than interact with menadione or GSH directly. Moreover, AIF doesn't show transferase catalytic site which reinforce the notion that AIF stabilizes conjugate product-thiodione.