Ahmad Thontowi

Optimization of Substrate and Starter Cell Concentrations for Dibenzothiopene Biodegradation by Indigeneous Marine Bacteria Mauricauda olearia LBF-1-0009, Alcanivorax xenomutants LBF-1-0018, and Stakelama pacifica LBF-1-0031

Dibenzothiophene (DBT) and its derivatives have been widely used as model organic sulfur compounds in petroleum, included their biodegradation process. The abilities of microorganisms to degrade pollutants are significantly influenced by various factors such as microbial species, nutrients and environmental parameters. In this research, we carried out further study to determine optimal condition for DBT biodegradation regarding with substrate and strains cell concentration by several indigenous marine bacteria from Indonesia. These three isolates were belong to Mauricauda olearia , Alcanivorax xenomutants , and Stakelama pacifica , with homology result 99% each. Optimal dibenzothiophene as substrate reached by all isolates is 100 ppm, while cell concentration or microbial numbers that gave highest growth for all isolates is 20 based on conversion of OD 600 nm measurement.

Polyaromatic Hydrocarbon Degradation and Dioxygenase Gene Detection from Alteromonas alvinellae Bt05

Bt05 is marine bacterium which was isolated from the Jakarta Bay, Indonesia. The aim of this study was to characterize PAHs-degrading property, molecular identification by partial analysis of 16S rRNA gene and to partially analyze dioxygenase gene of Bt05 isolate. Our further study on this isolate revealed that it could degrade three PAHs (phenanthrene, dibenzothiophene, fluorene) between 60%–90% within 11 days at 100 ppm level. This finding indicated the potential of the isolate for bioremediation of PAHs. The isolate was identified as Alteromonas alvinellae by phylogenetic analysis of 16S rRNA gene sequence. Sequence analysis of the PCR product of PAH dioxygenase genes amplified using two primer set (iiDA and ppAH) of the isolate were identified 97% as naphthalene dioxygenase gene ( pha Ac) and 58% as 1,2-dioxygenase.