Pronounced synergistic influence of mixed substrate cultivation on single step copolymer P(3HB-co-4HB) biosynthesis with a wide range of 4HB monomer composition

Abstract

BACKGROUND: Copolymer poly(3-hydroxybutyrate-co-4-hydroxybutyrate), P(3HB-co-4HB) has gained importance in biotechnological processes due to its potential as an absorbable material in biopharmaceutical applications. The aim of the present study was to investigate the implementation of mixed substrate cultivation concept in single step production of copolymer P(3HB-co-4HB). Evaluation of the sole carbon sources was first carried out to elucidate the difference in the monomer content of 4HB using different types and concentrations of carbon sources. This is followed by the study of mixed-substrate cultivation on copolymer biosynthesis. Finally, the molecular weight of copolymers with various 4HB monomer compositions was also determined. RESULTS: Experimentation using the sole carbon source recorded the highest PHA content, PHA concentration and 4HB monomer composition of 57 wt%, 3.1 g L −1 and 48 mol%, respectively. Manipulation of the carbon source combination showed the synergistic influence of the substrates mixture towards single-stage production of P(3HB-co-4HB), which enhanced the yield of copolymer P(3HB-co-4HB), to a maximum PHA content and concentration of 74 wt% and 6.9 g L −1 . In addition, 4HB monomer composition up to a maximum of 70 mol% was obtained. Molecular weight characterization showed the increase of 4HB monomer composition which led to the decrease of molecular weight from 369.3 kDa to 34.0 kDa. CONCLUSION:The mixed substrate cultivation was proven to be a promising strategy to increase both polymer production and 4HB monomer composition in single stage production. This serves as a platform for further bioprocess development of copolymer with various 4HB monomer compositions.

Biosynthetic enhancement of single-stage Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) production by manipulating the substrate mixtures

“…In other words, our findings suggest that different substrate combinations and concentrations exerted more influence on the molecular weight. This assertion is supported by our previous report in shake-flask fermentation [12]. However, in the case of the substrate mixture of γ + 1,6 and 1,4 + 1,6, when both the carbon sources in the substrate mixtures were supplied at medium concentration level (M γ +M 1,6 and M 1,4 + M 1,6 ), the M w and M n values were the lowest as compared to the combination of different concentration levels.…”

“…It was concluded that in single-stage cultivation, the bacterium has the ability to accumulate high PHA content with lower 4HB molar fraction [1]. However, in our recent report we demonstrated that the shake-flask scale research has not only revealed its potential in improving the copolymer accumulation, but it has also resulted in the accumulation of a wide range of 4HB monomer, ranging from 7 to 70 mol% [12]. This is a breakthrough study on single-stage biosynthesis of copolymer P(3HB-co-4HB), which resulted in the increase in monomer composition by using mixedsubstrate cultivation strategy.…”

En route to economical eco‐friendly solvent system in enhancing sustainable recovery of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) copolymer

“…The P(3HB‐ co ‐4HB) is a short‐chain‐length polyhydroxyalkanoate ( scl ‐PHA) which is like other PHAs, being produced under nutrient limited condition but with an excess carbon sources. It can be produced by various types of bacterial species such as Alcaligenes latus, Comamonas acidovarans, Cupriavidus necator and Hydrogenophage pseudoflava , with the addition of 4HB precursors such as γ‐butyrolactone, 1,4‐butanediol, 1,6‐hexanediol and 1,8‐octanediol . This 4HB‐incorporated thermoplastic has been reported to be a promising biomaterial, either in bio‐pharmaceutical application as the excipient in drugs or as wound dressing in medical application .…”

“…The P(3HB-co-4HB) is a short-chain-length polyhydroxyalkanoate (scl-PHA) which is like other PHAs, being produced under nutrient limited condition but with an excess carbon sources. It can be produced by various types of bacterial species such as Alcaligenes latus, Comamonas acidovarans, Cupriavidus necator and Hydrogenophage pseudoflava, with the addition of 4HB precursors such as γ-butyrolactone, 1,4-butanediol, 1,6-hexanediol and 1,8-octanediol [1][2][3][4]. This 4HB-incorporated thermoplastic has been reported to be a promising biomaterial, either in Correspondence: Prof. A.A. Amirul (amirul@usm.my) School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia Abbreviations: NaOH, Sodium hydroxide; NPCM, Non-polymeric cell material digestion; PHA, Polyhydroalkanoate; P(3HB-co-4HB), Poly(3-hydroxybutyrate-co-4-hydroxybutyrate); RSM, Response surface methodology bio-pharmaceutical application as the excipient in drugs [5] or as wound dressing in medical application [6].…”

Intensification of Synthesis of Practically Important Microbial Metabolites on Substrates Mixture

“…Біосинтез інших мікробних метаболітів на змішаних субстратах. Стратегія використання суміші субстратів використовується не лише для отримання ПАР, а й для інших практично цінних мікробних метаболітів: ліпідів [16][17][18][19][20][21][22][23][24], екзополісахаридів [25][26][27], пілігідроксиалканоатів [28][29][30], ферментів [31][32][33], органічних кислот [34][35][36][37][38], пропандіолу [39,40], біоетанолу [41], біоводню [42,43].…”