Identification and Molecular Characterization of Polyhydroxyalkanoate Producing Bacterial Isolates from Dambal Lake Soil Sediment

Abstract

Plastics are conventional products with molding features . These plastic wastes accumulation are used to affect both domestic animals and wild life. Polyhydroxyalkonoate (PHA) is a natural bioplastic that can be produced by various bacterial cells during non-carbon sources are available. The present study was aimed at identification and molecular characterization of PHA producing bacterial isolates from Lake Dambel Oromia region, Ethiopia. PHA producing bacterial isolates were screened using SBB and NBAdyes. These NBA positive isolates were identified by using Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI TOF- MS). PCR amplification was carried out for certain NBA positive isolates. Optimization for culture conditions were conducted for frequently isolated and with stronger fluorescent intensity were conducted. The 16SrRNA genes sequence for isolate with more fluorescent intensity was perfomed. Phylogentic tree was constructed after other related bacterial strain were collected from Gene Bank database using EzTaxon server. In this study, total of 40 bacterial isolate were collected. Out of 40 isolates, 32 and 26 of them were found to be positive for SBB and NBA staining respectively. These NBA positive isolates were identified and found to be Pseudomonas spp., Bacillus spp., Klebsella sp and Staphlococcus sp. The majority of the PHA granules positive isolates were Identified as Psedomonas spp. using MALDI TOF MS techniqhes. PHA gene amipilification were checked and 540bp amplicons were obatined for various species of Pseudomonas isolates and one single Bacillus sp. The present PHA producing Psedomonas sp. DLSPI-12 isolate was found to produce more PHA granules with higher CDW and OD600nm using Glucose as a carbon source at 25oC and pH 7. It is possible to conclude that Pesudomonas aeuruginosa DLSPI-12 can be employed for degrading wastes in enrich with cellulosic materials, for production of bioplastics (PHA) which is biological degradable . It will take further research to address obstacles in the way of determining the productivity of bioplastic production from micro organisms .