Screening of different contaminated environments for polyhydroxyalkanoates-producing bacterial strains

Abstract

Total sixteen bacterial strains were isolated and purified from the samples collected from sugarcane molasses soil, sewage water and long-chain-hydrocarbon-contaminated area of the Punjab University, Lahore, Pakistan. Tolerance to different antibiotics was studied and strains showed multiple antibiotic resistance. All strains were characterized for Gram stain, biochemical reactions and polyhydroxyalkanoate (PHA) production. Total fourteen strains were Gram negative and two were Gram positive, while biochemically nine PHA producers showed affiliation to Pseudomonas, Enterobacter, Citrobacter, Bacillus and Escherichia. Screening for PHA production was done by Sudan black staining and nine out of sixteen strains exhibited PHA producing ability. PHA production was optimized for different growth parameters, like nitrogen concentration, pH and temperature. PHA extraction was done by solvent extraction method. Bacterial strains US1 and M1 accumulated up to 30% PHA of their cell dry weight on PHA extraction by solvent extraction method. Bacterial strain US1 was identified by 16S rRNA gene analysis as P. aeruginosa (DQ455691). PHA production was confirmed by PCR amplification of 500 bp fragment from PHA polymerase (Pha C) gene; five strains from nine PHA producers gave positive results on PCR. Pha C gene fragment of US1 was sequenced and submitted to Gene Bank under the accession number DQ455690. The amino acid sequence showed homology using the protein BLAST at 129-132 sites with different PHA synthases of the Pseudomonas sp.

Screening for polyhydroxyalkanoate (PHA)-producing bacterial strains and comparison of PHA production from various inexpensive carbon sources

“…16S rRNA gene was amplified using Primus96 (PeQLab) with PCR master mix forward primer 16S-3, CCCGGGAACGTATTCACCG and reverse primer 16S-5, GCYTAAYACATGCAAGTCGA (Rehman et al 2007). PCR was carried out by denaturing DNA at 110°C for 10 min followed by 30 cycles of amplification (95°C for 2 min, 52°C for 1 min and 72°C for 2 min).…”

Antibiotics Sensitivity and Heavy Metals Resistance in PHB-Producing Bacilli Isolated from Eastern Province, Saudi Arabia

“…agriculture, hospitals, animal farming and industry, might pose serious pressure on microbes leading to mutations and other modifications. Therefore, it is recommended to explorer the PHB-producing strains regarding resistance to heavy metal and antibiotics for controlling contamination before industrial production of the biopolymer (De Lima et al, 1999;Rehman et al, 2007). Except ampicillin, erythromycin, amoxicillin and neomycin, most of PHB-producing candidates showed higher susceptibility to antibiotics (Fig.…”

“…De Lima et al (1999) mentioned that PHA biopolymers production in industrial scale is strongly affected by heavy contamination from environment in the fermenter. Therefore, it is highly crucial to exploit the potent biopolymer producing strains regarding antibiotics and heavy metal resistance for controlling contamination before industrial production of the polymer (De Lima et al, 1999;Rehman et al, 2007;Razzaq et al, 2010;Naheed et al, 2011).…”

Animal fat and glycerol bioconversion to polyhydroxyalkanoate by produced water bacteria

“…Isolated bacterial strains were screened for PHA production ability by using PHA detection media (39) agar plates (40) supplemented with Nile blue A (41)(42)(43)(44) or Nile red (45-47) for direct screening. After 24 h incubation, all plates were observed under UV light.…”