Characterization of bioplastics produced by haloarchaeon Haloarcula sp strain NRS20 using cost-effective carbon sources

Abstract

As good models for developing techniques, Haloarchaea are using as cell factories to produce a considerable concentration of bioplastics, polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), and polyhydroxyvalerate (PHV). In this study, low-cost carbon sources by Sudan Black staining was applied for screening haloarchaea a hypersaline environment (southern coast of Jeddah, Saudi Arabia). The growth of the selected isolate and PHB-production under different carbon sources, temperature, pH values and NaCl concentrations were investigated. The biopolymer was extracted and quantitatively measured. The biopolymer was qualitatively identified by Fourier-transform infra-red analysis (FTIR) and High Performance Liquid Chromatography (HPLC). The potential Haloarcula sp strain NRS20 (MZ520352) could significantly accumulate PHB under nutrient-limiting conditions using different carbon sources including starch, carboxymethyl cellulose (CMC), sucrose, glucose and glycerol with 23.83%, 14%, 11%, 12% and 8% of PHB/CDW respectively under 25% NaCl (w/v), pH 7, at 37 °C. The results of FTIR pattern indicated that the significant peak at 1709.22 cm⁻¹ confirmed the presence of the ester carbonyl-group (C=O) which is typical of PHB. HPLC analysis indicated that produced PHB was detected at 7.5 min with intensity exceeding the standard PHB at 8.0 min. Few potential species of haloarchaea were reported for economical PHB-production, here, Haloarcula sp strain NRS20 showed high content of PHB, exhibited a promising PHB-producer using inexpensive sources of carbon.