Universitas Scientiarum (Jun 2023)
Isolation and characterization of polyhydroxyalkanoate-producing bacteria from seawater samples (Tumaco)
Abstract
Introduction. Polyhydroxyalkanoates (PHA) are a family of polyesters than comprise > 100 types of homo and heteropolymers that can be produced from renewable carbon sources by microorganisms, making it a sustainable and environmentally friendly material as substituent of plastics. Currently, the production of the biopolymers is not competitive in terms of cost and yield comparatively with synthetic polymers; however, such production by different bacterial strains may provide economic and ecological viability if there are investments in this area, and there are evidence that bioplastic accumulates antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) in marine sediments. Objective. The aim of this work was to isolate and characterize molecularly and biochemically PHA-producing bacteria of water samples obtained from five sites (gas stations) in coastal regions of Tumaco Island, Nariño-Colombia, and determinate the antimicrobial susceptibility of isolates because the biological role goes beyond their storage function, since they presence in cytoplasm enhances stress resistance of microorganisms. Materials and methods. Bacterial colonies were isolated from samples water. A viable colony staining method using Nile red was used to screen for PHA-producing bacteria. Colonies were isolated, characterized via biochemical, microbial, and molecular methods, and tested for antimicrobial susceptibility and fermentation. The crude extract was analyzed by GC-MS/MS techniques. Results. More than thirty-eight strains were identified as potential PHA-positive isolates from this screening approach but, just one isolated was viable in PHA production (T2-25A). All isolates were resistant to metronidazole, ampicillin, trimethoprim sulfamethoxazole, cephalothin, ceftriaxone, and cefazolin, and 27:3 % of isolates were resistant to novobiocin. Conclusions. One promising PHA-producing isolate was obtained. Nevertheless, this information will complement future studies of the conditions necessary to produce PHA. Moreover, antibiotic resistance data have attracted attention, especially because of the origin of the source waters of the isolates.
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