A four-microorganism three-step fermentation process for producing medium-chain-length polyhydroxyalkanoate from starch

Yang, Xiaohui; Li, Suhang; Jia, Xiaoqiang

doi:10.1007/s13205-020-02347-6

Cited by 5 publications

(9 citation statements)

References 25 publications

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“…In these latter fermentations, a greater use of ESBPP is achieved, although a mixture of both acids is obtained. For instance, both acetic acid and LA can be used for polyhydroxyalkanoate production by fermentation with pure or mixture culture 35 or as a preservative in the food industry 36 …”

Section: Resultsmentioning

confidence: 99%

Valorisation of fungal hydrolysates of exhausted sugar beet pulp for lactic acid production

et al. 2021

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BACKGROUND Exhausted sugar beet pulp pellets (ESBPP) were used as raw material for lactic acid (LA) fermentation. The enzymatic hydrolysis of ESBPP was performed with the solid obtained after the fungal solid‐state fermentation of ESBPP as a source of hydrolytic enzymes. Subsequently, a medium rich in glucose and arabinose was obtained, which was used to produce LA by fermentation. For LA production, two Lactobacillus strains were assayed and the effects of the supplementation of the hydrolysate with a nitrogen source and the mode of pH regulation of the fermentation were investigated. Moreover, a kinetic model for LA fermentation by Lactobacillus plantarum of ESBPP hydrolysates was developed. RESULTS L. plantarum produced a LA concentration 34% higher than that produced by L. casei. The highest LA concentration (30 g L−1) was obtained with L. plantarum when the hydrolysate was supplemented with 5 g L−1 yeast extract and the pH was controlled with CaCO3. The concentration of acetic acid differed depending on the concentration of CaCO3 added, producing its maximum value with 27 g L−1 CaCO3. The proposed kinetic model was able to predict the evolution of substrates and products depending on the variation of the pH in the hydrolysate, according to the amount of CaCO3 added. CONCLUSIONS ESBPP can be revalorised to produce LA. A pure LA stream or a mixture of LA and acetic acid, depending on the pH control method of the fermentation, can be produced. Thus, this control is of great interest depending on the destination of the effluent. © 2020 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Valorisation of fungal hydrolysates of exhausted sugar beet pulp for lactic acid production

et al. 2021

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“…In addition, mcl-PHA with a high ratio of dominant monomer tends to display better material properties. 9,10 mcl-PHA is mainly produced via the fatty acid de novo biosynthesis pathway through ACP transacylase (PhaG), acyl-CoA-synthase (AlkK), and PHA polymerase (PhaC) from unrelated carbon sources or the fatty acid β-oxidation pathway through enoyl-CoA hydratase (PhaJ) and PhaC from relevant fatty acids. 11 However, two carbon units of fatty acids are removed as an acetyl-CoA in each cycle of fatty acid βoxidation, which is commonly considered as the major consumer of mcl-PHA.…”

Section: ■ Introductionmentioning

confidence: 99%

“…19 Nevertheless, most engineered strains show relatively low performance in both the CDW and the titer of mcl-PHA at the shake-flask level, which thereby hampers large-scale fermentation for the desired production. 10,20 In addition, engineering of Pseudomonas chlororaphis, which is a valuable chassis for the biosynthesis of diverse valueadded products, 21−23 for improved mcl-PHA production is infrequently reported. P. chlororaphis HT66 isolated by our lab from rhizosphere soil of rice is an environment-friendly biocontrol bacterium that is capable of producing phenazine-1-carboxamide (PCN) at a high titer.…”

Section: ■ Introductionmentioning

confidence: 99%

“…scl-PHA has high brittleness, hardness, and poor tensile strength, while mcl-PHA exhibits better flexibility, thermoplasticity, and elasticity. , Hence, mcl-PHA is a promising elastomer or blending polymer to ameliorate the physicochemical properties of PHAs and other biodegradable polymers. In addition, mcl-PHA with a high ratio of dominant monomer tends to display better material properties. , …”

Section: Introductionmentioning

confidence: 99%

“…Overexpression of the phaG gene in Pseudomonas mendocina NK-U-2 slightly decreased the cell dry weight (CDW) but notably increased the mcl-PHA titer from 24.5 to 51.2 wt % . Nevertheless, most engineered strains show relatively low performance in both the CDW and the titer of mcl-PHA at the shake-flask level, which thereby hampers large-scale fermentation for the desired production. , In addition, engineering of Pseudomonas chlororaphis, which is a valuable chassis for the biosynthesis of diverse value-added products, − for improved mcl-PHA production is infrequently reported.…”

Section: Introductionmentioning

confidence: 99%

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Biosynthesis and Characterization of Medium-Chain-Length Polyhydroxyalkanoate with an Enriched 3-Hydroxydodecanoate Monomer from a Pseudomonas chlororaphis Cell Factory

Deng

Wang

et al. 2021

J. Agric. Food Chem.

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Polyhydroxyalkanoates (PHAs) have been reported with agricultural and medical applications in virtue of their biodegradable and biocompatible properties. Here, we systematically engineered three modules for the enhanced biosynthesis of medium-chain-length polyhydroxyalkanoate (mcl-PHA) in Pseudomonas chlororaphis HT66. The phzE, fadA, and fadB genes were deleted to block the native phenazine pathway and weaken the fatty acid β-oxidation pathway. Additionally, a PHA depolymerase gene phaZ was knocked out to prevent the degradation of mcl-PHA. Three genes involved in the mcl-PHA biosynthesis pathway were co-overexpressed to increase carbon flux. The engineered strain HT4Δ::C1C2J exhibited an 18.2 g/L cell dry weight with 84.9 wt % of mcl-PHA in a shake-flask culture, and the 3-hydroxydodecanoate (3HDD) monomer was increased to 71.6 mol %. Thermophysical and mechanical properties of mcl-PHA were improved with an enriched ratio of 3HDD. This study demonstrated a rational metabolic engineering approach to enhance the production of mcl-PHA with the enriched dominant monomer and improved material properties.

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Current trends in medium‐chain‐length polyhydroxyalkanoates: Microbial production, purification, and characterization

Hahn,

Alzate,

Leonhardt

et al. 2024

Engineering in Life Sciences

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Polyhydroxyalkanoates (PHAs) have gained interest recently due to their biodegradability and versatility. In particular, the chemical compositions of medium‐chain‐length (mcl)‐PHAs are highly diverse, comprising different monomers containing 6–14 carbon atoms. This review summarizes different feedstocks and fermentation strategies to enhance mcl‐PHA production and briefly discusses the downstream processing. This review also provides comprehensive details on analytical tools for determining the composition and properties of mcl‐PHA. Moreover, this study provides novel information by statistically analyzing the data collected from several reports on mcl‐PHA to determine the optimal fermentation parameters (specific growth rate, PHA productivity, and PHA yield from various structurally related and unrelated substrates), mcl‐PHA composition, molecular weight (MW), and thermal and mechanical properties, in addition to other relevant statistical values. The analysis revealed that the median PHA productivity observed in the fed‐batch feeding strategy was 0.4 g L−1 h−1, which is eight times higher than that obtained from batch feeding (0.05 g L−1 h−1). Furthermore, 3‐hydroxyoctanoate and ‐decanoate were the primary monomers incorporated into mcl‐PHA. The investigation also determined the median glass transition temperature (−43°C) and melting temperature (47°C), which indicated that mcl‐PHA is a flexible amorphous polymer at room temperature with a median MW of 104 kDa. However, information on the monomer composition or heterogeneity and the associated physical and mechanical data of mcl‐PHAs is inadequate. Based on their mechanical values, the mcl‐PHAs can be classified as semi‐crystalline polymers (median crystallinity 23%) with rubber‐like properties and a median elongation at break of 385%. However, due to the limited mechanical data available for mcl‐PHAs with known monomer composition, identifying suitable processing tools and applications to develop mcl‐PHAs further is challenging.

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A four-microorganism three-step fermentation process for producing medium-chain-length polyhydroxyalkanoate from starch

Cited by 5 publications

References 25 publications

Valorisation of fungal hydrolysates of exhausted sugar beet pulp for lactic acid production

Valorisation of fungal hydrolysates of exhausted sugar beet pulp for lactic acid production

Biosynthesis and Characterization of Medium-Chain-Length Polyhydroxyalkanoate with an Enriched 3-Hydroxydodecanoate Monomer from a Pseudomonas chlororaphis Cell Factory

Current trends in medium‐chain‐length polyhydroxyalkanoates: Microbial production, purification, and characterization

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