Enhanced polyhydroxybutyrate (PHB) production by newly isolated rare actinomycetes Rhodococcus sp. strain BSRT1-1 using response surface methodology

Abstract

Poly-β-hydroxybutyrate (PHB) is a biodegradable polymer, synthesized as carbon and energy reserve by bacteria and archaea. To the best of our knowledge, this is the first report on PHB production by a rare actinomycete species, Rhodococcus pyridinivorans BSRT1-1. Response surface methodology (RSM) employing central composite design, was applied to enhance PHB production in a flask scale. A maximum yield of 3.6 ± 0.5 g/L in biomass and 43.1 ± 0.5 wt% of dry cell weight (DCW) of PHB were obtained when using RSM optimized medium, which was improved the production of biomass and PHB content by 2.5 and 2.3-fold, respectively. The optimized medium was applied to upscale PHB production in a 10 L stirred-tank bioreactor, maximum biomass of 5.2 ± 0.5 g/L, and PHB content of 46.8 ± 2 wt% DCW were achieved. Furthermore, the FTIR and 1H NMR results confirmed the polymer as PHB. DSC and TGA analysis results revealed the melting, glass transition, and thermal decomposition temperature of 171.8, 4.03, and 288 °C, respectively. In conclusion, RSM can be a promising technique to improve PHB production by a newly isolated strain of R. pyridinivorans BSRT1-1 and the properties of produced PHB possessed similar properties compared to commercial PHB.

Biosynthesized Poly(3-Hydroxybutyrate) on Coated Pineapple Leaf Fiber Papers for Biodegradable Packaging Application

“…The Rhodococcus pyridinivorans BSRT1–1, a rare actinomyces strain, produced high yield of P(3-HB) (46.8 ± 2.0% based on dry cell weight) in a 10 L bioreactor under the optimum condition previously published by our research group [ 22 ]. In this study, gel permeation chromatography (GPC) was used to evaluate the molecular weight of P(3-HB) to understand the general characteristics of the P(3-HB) polymer.…”

“…Rhodococcus pyridinivorans BSRT1–1 was isolated from the soil by Enzyme and Microbial Technology Laboratory, Kasetsart Agricultural and Agro-Industrial Product Improvement Institute (KAPI), Kasetsart University, Bangkok, Thailand, which was previously identified as a high potential P(3-HB) producing bacterium [ 22 ]. The minimal medium (MM) was used for P(3-HB) production consisting of NH 4 Cl, 0.5 g/L; KH 2 PO 4 , 2.8 g/L; Na 2 HPO 4 , 3.32 g/L; MgSO 4 ·7H 2 O, 0.25 g/L, and 1 ml/L of trace element (TE) solution.…”

“…Production and purification of P(3-HB) were conducted in accordance with the method described previously [ 22 ]. Briefly, R. pyridinivorans BSRT1–1 was activated in tryptic soy agar (TSA) plate and incubated at 35 °C for 24 h. The respective colonies were transferred into 250 flask containing 50 mL of in tryptic soy broth (TSB) and incubated in a rotary shaker at 35 °C, 180 rpm for 18 h. The obtained culture was then inoculated into a 10 L stirred tank fermenter containing 6 L of minimal medium (MM) at 35 °C for 48 h with aeration rate at 0.75 vvm, agitation rate at 180 rpm and controlling of pH to neutral within fermentation period.…”

“…However, the dip coating is considered to be a facile method of applying an aqueous coating solution over the paper, which is practically applied in the laboratory scale and the coating performance can be quickly determined [ 10 ]. We recently reported the production of biosynthesized P(3-HB) by a newly isolated rare actinomyces Rhodococcus pyridinivorans BSRT1–1 [ 22 ]. However, the application of this newly biosynthesized has not been reported so far.…”

Surface Characterization and Physiochemical Evaluation of P(3HB-co-4HB)-Collagen Peptide Scaffolds with Silver Sulfadiazine as Antimicrobial Agent for Potential Infection-Resistance Biomaterial

“…Polyhydroxyalkonates (PHAs) are insoluble granules accumulated in cell cytoplasm as carbon and energy storage compounds under stress conditions [3][4][5]. PHAs are a biodegradable thermoplastic which exhibit similar thermo-mechanical properties to synthetic polymers [6].…”