nan Akhmaloka

Microbial Diversity of Acidic Hot Spring (Kawah Hujan B) in Geothermal Field of Kamojang Area, West Java-Indonesia

Microbial communities in an acidic hot spring, namely Kawah Hujan B, at Kamojang geothermal field, West Java-Indonesia was examined using culture dependent and culture independent strategies. Chemical analysis of the hot spring water showed a characteristic of acidic-sulfate geothermal activity that contained high sulfate concentrations and low pH values (pH 1.8 to 1.9). Microbial community present in the spring was characterized by 16S rRNA gene combined with denaturing gradient gel electrophoresis (DGGE) analysis. The majority of the sequences recovered from culture-independent method were closely related to Crenarchaeota and Proteobacteria phyla. However, detail comparison among the member of Crenarchaeota showing some sequences variation compared to that the published data especially on the hypervariable and variable regions. In addition, the sequences did not belong to certain genus. Meanwhile, the 16S Rdna sequences from culture-dependent samples revealed mostly close to Firmicute and gamma Proteobacteria.

Simple Enrichment and Independent Cultures to Expand Bacterial Community Analysis from Gedongsongo Hot Spring

Denaturing gradient gel electrophoresis was used to identify bacterial communities from Gedongsongo hot spring, Indonesia, by culture-independent and -dependent procedures. Predominant species were found to be closely related to beta-proteobacteria, particularly from genus Ralstonia and Delftia. Other species present include alpha- and gamma-proteobacteria and Thermus groups. Some of the strains showed unique 16S rDNA sequences.

Amplification of thermostable lipase genes fragment from thermogenic phase of domestic waste composting process

Lipases are lipolytic enzymes, catalyze the hydrolysis of fatty acid ester bonds of triglycerides to produce free fatty acids and glycerol. The enzyme is widely used in various fields of biotechnological industry. Hence, lipases with unique properties (e.g.thermostable lipase) are still being explored by variation methods. One of the strategy is by using metagenomic approach to amplify the gene directly from environmental sample. This research was focused on amplification of lipase gene fragment directly from the thermogenic phase of domestic waste composting in aerated trenches. We used domestic waste compost from waste treatment at SABUGA, ITB for the sample. Total chromosomal DNA were directly extracted from several stages at thermogenic phase of compost. The DNA was then directly used as a template for amplification of thermostable lipase gene fragments using a set of internal primers namely Flip-1a and Rlip-1a that has been affixed with a GC clamp in reverse primer. The results showed that the primer...

Simple and Easy Method to Synthesize Chicken Eggshell Based Hydroxyapatite

Hydroxyapatite is a common material applied in orthophedia and dentistry. The application of this material is currently expanded to biotechnology field, such as to be used as support materials for enzymes immobilization. Hydroxyapatite can be synthesized by utilizing chicken eggshell waste in household and food industries. This work is aiming to provide a simple and easy method to synthesize hydroxyapatite from chicken eggshell. The synthesis of hydroxyapatite was firstly carried out by reacting chicken eggshell powder (calcium precursor) with (NH4)2HPO4 via modified precipitation at room temperature and normal atmospheric pressure. The mixture was then stirred variably for 1, 2, 3, and 24 hours. X-ray diffraction (XRD) analysis suggests that hydroxyapatite powder derived from this procedure formed a single-phase crystal and it was completely formed after the reaction has run for 1 hour. The scanning electron microscopy (SEM) image showed that the synthesized hydroxyapatite forms a rice-like pattern. The size of hydroxyapatite crystal measured at (002) plane was about 45 nm. Our result showed that simple modified precipitation at room temperature and normal atmospheric pressure in one hour reaction has successfully synthesized hydroxyapatite from chicken eggshell.

The Role of Electrostatic Interactions on Klentaq1 Insight for Domain Separation

We investigated the relationship between the thermostability of Klentaq1 and factors stabilizing interdomain interactions. When thermal adaptation of Klentaq1 was analyzed at the atomic level, the protein was stable at 300 and 350 K. It gradually unfolded at 373 K and almost spontaneously unfolded at 400 K. Domain separation was induced by disrupting electrostatic interactions in two salt bridges formed by Lys354-Glu445 and Asp371-Arg435 on the interface domain. The role of these interactions in protein stability was evaluated by comparing free energy solvation (ΔΔGsolv) between wild type and mutants. Substitution of Asp371 by Glu or Asn, and also Glu445 by Asn resulted in a positive value of ΔΔGsolv, suggesting that mutations destabilized the protein structure. Nevertheless, substitution of Glu445 by Asp gave a negative value to ΔΔGsolv reflecting increasing protein stability. Our results demonstrate that interactions at the interface domains of Klentaq1 are essential factors correlated with the Klentaq1 thermostability.