Ethylic Esters as Green Solvents for the Extraction of Intracellular Polyhydroxyalkanoates Produced by Mixed Microbial Culture

Alfano, Sara; Lorini, Laura; Majone, Mauro; Sciubba, Fabio; Valentino, Francesco; Martinelli, Andrea

doi:10.3390/polym13162789

Cited by 16 publications

(17 citation statements)

References 52 publications

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“…As expected from the recovery data (see Figure 3 ), the lowest A PHA values were computed from the DRIFT spectra of samples A and B. Thus, digestion with NaOH produced PHA with significant amounts of residues, which was expected because similar trends were noted for wet biomasses [ 35 ] or other biomasses with similar PHA content [ 26 ]. The FTIR analysis shows that mastication was effective in reducing the amount of non-PHA residues in the extracted films.…”

Section: Resultssupporting

confidence: 67%

Can Biomass Mastication Assist the Downstreaming of Polyhydroxyalkanoates Produced from Mixed Microbial Cultures?

et al. 2023

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Polyhydroxyalkanoates (PHAs) are natural polyesters which biodegrade in soils and oceans but have more than double the cost of comparable oil-based polymers. PHA downstreaming from its biomass represents 50% of its overall cost. Here, in an attempt to assist downstreaming, mastication of wet biomasses is tested as a new mechanical continuous biomass pretreatment with potential for industrial upscaling. Downstreaming conditions where both product recovery and purity are low due to the large amount of treated wet biomass (50% water) were targeted with the following process: extraction of 20 g in 100 mL solvent at 30 °C for 2 h, followed by 4.8 h digestion of 20 g in 0.3 M NaOH. Under the studied conditions, NaOH digestion was more effective than solvent extraction in recovering larger PHA amounts, but with less purity. A nearly 50% loss of PHA was seen during digestion after mastication. PHAs downstreamed by digestion with large amounts of impurities started to degrade at lower temperatures, but their melt elasticity was thermally stable at 170 °C. As such, these materials are attractive as fully PHA-compatible processing aids, reinforcing fillers or viscosity modifiers. On the other hand, wet biomass mastication before solvent extraction improves PHA purity and thermal stability as well as the melt rheology, which recovers the viscoelasticity measured with a PHA extracted from a dried biomass.

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Section: Resultssupporting

confidence: 67%

Can Biomass Mastication Assist the Downstreaming of Polyhydroxyalkanoates Produced from Mixed Microbial Cultures?

et al. 2023

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“…Comparable studies have reported that ethyl acetate has been successfully used as a solvent for the extraction of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB-co-3HHx) containing >15 mol% of HHx, resulting in a recovery yield of 99 wt% at 100°C ( Riedel et al, 2013 ). Additionally, this study indicated the necessity to perform the extraction on dried cells since the presence of water had a double effect on ester hydrolysis and the reduction of the solvating power ( Alfano et al, 2021 ).…”

Section: Discussionmentioning

confidence: 96%

“…However, very high temperatures could have a negative impact on the yield. At very high temperatures, the produced PHB could be further decomposed into smaller molecules or organic acids that consequently decrease the extraction yield ( Aramvash et al, 2018 ; Alfano et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Optimization for the efficient recovery of poly(3-hydroxybutyrate) using the green solvent 1,3-dioxolane

Wongmoon

Napathorn²

2022

Front. Bioeng. Biotechnol.

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In this study, a simple non-toxic recovery process of biodegradable poly(3-hydroxybutyrate) (PHB) using the green solvent 1,3-dioxolane and water was successfully developed. The critical parameters were optimized, and the process platform was scaled up from 2 ml to 1,000 ml for the efficient recovery of PHB. The physical parameters including continuous shaking, ultrasonication, extraction using the Soxhlet extractor, diluted 1,3-dioxolane, reused 1,3-dioxolane, and cell rupture by steam explosion prior to solvent extraction were carefully investigated. The results showed that continuous shaking played a major role in increasing the recovery efficiency during the scale-up process. The PHB extraction at 2 ml from dried cells at 80°C with 100 rpm of shaking speed for 5 h resulted in a recovery yield of 96.6 ± 0.1% with purity up to 99.1 ± 0.6% and that from wet cells under the same condition resulted in a recovery yield of 94.6 ± 4.8% and purity of 97.0 ± 0.1%. It should be noted that the PHB extracted from wet cells at room temperature with 150 rpm of shaking speed for 36 h resulted in a recovery yield of 93.5 ± 0.7% and purity of 97.7 ± 1.3% and had an MW of 3.1×105, MN of 2.7×105, and polydispersity index of 1.1. The direct scale-up process at 1,000 ml showed comparable results in purity, recovery yield, molecular weight distribution, thermal properties, and mechanical properties. The PHB extraction from dried cells gave the highest purity of 99.3 ± 0.5% and recovery of 94.0 ± 0.3%, whereas the PHB extraction from wet cells gave a purity of 90.3 ± 1.5% and recovery of 92.6 ± 1.0%. The novel recovery process showed its feasibility to be applied on an industrial scale.

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“…In turn, the wide range of substrates suitable for MMC-PHA production manifests in the wide range of thermoplastic and elastomeric properties of the synthetized PHA, including poly(3-hydroxybutyrate) (P(3HB)), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)), copolymers with variable 3-hydroxyvalerate (3HV) content, poly(4-hydroxybutyrate) (P(4HB)) and related copolymers, and poly(3-hydroxyhexanoate) (P(3HH)) and related copolymers [40][41][42]. PHA's properties mainly depend on the length and composition of the side chains-the literature states that the addition of monomers such as 3HV, and less frequently 3HH, to a P(3HB) backbone causes a reduction in the crystallinity and the melting temperature, as well as increasing the flexibility [43]. Indeed, P(3HB) is a very highly crystalline and stiff material, but at the same time, it is also brittle; its melting temperature is generally higher than those of copolymers (around 170-180 • C) and close to the degradation temperature (165-170 • C) [44].…”

Section: Bioprocess For Pha Production From Terrestrial Bacterial Str...mentioning

confidence: 99%

From Organic Wastes and Hydrocarbons Pollutants to Polyhydroxyalkanoates: Bioconversion by Terrestrial and Marine Bacteria

et al. 2022

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The use of fossil-based plastics has become unsustainable because of the polluting production processes, difficulties for waste management sectors, and high environmental impact. Polyhydroxyalkanoates (PHA) are bio-based biodegradable polymers derived from renewable resources and synthesized by bacteria as intracellular energy and carbon storage materials under nutrients or oxygen limitation and through the optimization of cultivation conditions with both pure and mixed culture systems. The PHA properties are affected by the same principles of oil-derived polyolefins, with a broad range of compositions, due to the incorporation of different monomers into the polymer matrix. As a consequence, the properties of such materials are represented by a broad range depending on tunable PHA composition. Producing waste-derived PHA is technically feasible with mixed microbial cultures (MMC), since no sterilization is required; this technology may represent a solution for waste treatment and valorization, and it has recently been developed at the pilot scale level with different process configurations where aerobic microorganisms are usually subjected to a dynamic feeding regime for their selection and to a high organic load for the intracellular accumulation of PHA. In this review, we report on studies on terrestrial and marine bacteria PHA-producers. The available knowledge on PHA production from the use of different kinds of organic wastes, and otherwise, petroleum-polluted natural matrices coupling bioremediation treatment has been explored. The advancements in these areas have been significant; they generally concern the terrestrial environment, where pilot and industrial processes are already established. Recently, marine bacteria have also offered interesting perspectives due to their advantageous effects on production practices, which they can relieve several constraints. Studies on the use of hydrocarbons as carbon sources offer evidence for the feasibility of the bioconversion of fossil-derived plastics into bioplastics.

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Ethylic Esters as Green Solvents for the Extraction of Intracellular Polyhydroxyalkanoates Produced by Mixed Microbial Culture

Cited by 16 publications

References 52 publications

Can Biomass Mastication Assist the Downstreaming of Polyhydroxyalkanoates Produced from Mixed Microbial Cultures?

Can Biomass Mastication Assist the Downstreaming of Polyhydroxyalkanoates Produced from Mixed Microbial Cultures?

Optimization for the efficient recovery of poly(3-hydroxybutyrate) using the green solvent 1,3-dioxolane

From Organic Wastes and Hydrocarbons Pollutants to Polyhydroxyalkanoates: Bioconversion by Terrestrial and Marine Bacteria

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