Molecular systematic and phylogenetic analysis of indigenous bacterial isolates with potential as bioremediation agent based on 16S rRNA gene analysis

Abstract

Liquid biomedical waste is a form of medical waste from community health centers (Pusat Kesehatan Masyarakat or Puskesmas) with high levels of health hazardous organic contaminants. Bioremediation is an alternative way to eliminate toxic components in liquid waste. A bacteria community that can be used as component of organic waste bioremediation is indigenous hydrolytic and non-pathogenic to low-pathogenic bacteria. From previous studies, 4 hydrolytic indigenous bacterial isolates with such characteristics were obtained from liquid clinical wastes of two health centers in Semarang City, namely H1, H3, H5 (from Puskesmas Halmahera), and T3 (from Puskesmas Tlogosari Kulon). This study aimed to reveal the molecular identity and kinship these bacterial isolates to understand more of their properties as consortium of bioremediation agent. Molecular identification and phylogenetic tree construction works were carried out based on 16S rRNA gene sequences. Sequences of 16S rRNA gene sequences were obtained by isolation and gene amplification using the PCR method followed by sequencing. Based on the results of molecular identification, the four isolates studied were in the same class, namely Gammaproteobacter with Phylum Proteobacter. H1 bacterial isolates have 98.01% similarity with Acinetobacter schindleri. H3 and H5 isolates share the same genus, Stenotrophomonas, with 99.79% similarity with S. maltophiphila and 97.69% with S. acidaminiphila, respectively. T3 isolate had a similarity of 98.85% with Pararheinheimera aquatica species, which was widely known as a potent bioremediation agent. The phylogenetic tree design with the MEGA 6 program showed that the H3 and H5 isolates had the closest kinship compared to the other two isolates, while the T3 isolates had the farthest relationship with the 3 other isolates. This is in line with the fact that T3 isolate was originated from a different location separating it from 3 other isolates.