Polyhydroxyalkanoate (PHA): Properties and Modifications

Sharma, Vibhuti; Sehgal, Rutika; Gupta, Reena

doi:10.1016/j.polymer.2020.123161

Cited by 197 publications

(98 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In developed countries, no more than 16–18% of plastic waste is recycled [ 5 ]. It is mostly landfilled, posing a global environmental problem [ 6 , 7 ], causing large-scale pollution, upsetting the stability and disrupting the structure of natural ecosystems, and threatening human health [ 8 ]. That is why it is important to research and develop biodegradable plastics as an alternative to synthetic materials [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…PHAs are synthesized by prokaryotes from various substrates, including waste products [ 18 , 19 , 20 , 21 ]. Development of PHAs was a notable event for biotechnology of degradable materials [ 6 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Monomer composition of PHAs determine their basic properties (crystallinity, thermal and molecular-weight properties, biodegradability), which vary widely, enabling fabrication of products with diverse physical/mechanical characteristics [ 15 , 29 , 30 , 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

“…P(3HB)-based products are degraded slowly, and implants may cause pronounced foreign body reaction [ 42 , 43 ]. Properties of polymeric materials, including P(3HB), can be improved by using biological, chemical, and physical methods, such as fabrication of P(3HB) composites with other materials, biosynthesis of PHA copolymers, chemical modification, and physical treatment of the surface of polymer products [ 6 , 25 , 27 , 44 , 45 , 46 , 47 , 48 ]. These methods help, more effectively or less effectively, change the properties of polymer products, increase their biodegradation rate, enhance their flexibility and mechanical strength, increase surface hydrophilicity and porosity to facilitate cell attachment, improve gas dynamic properties of the products, and enhance their permeability to substrates and metabolic products of cells and tissues.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition

et al. 2021

View full text Add to dashboard Cite

The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92° and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80–56° and surface energy and roughness increased to 41–57 mN/m and 172–290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76–80°) and reduced roughness parameters (to 40–45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67–76°), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition

et al. 2021

View full text Add to dashboard Cite

show abstract

“…These are the polymers of hydroxyacids produced by number of microorganisms including bacteria. PHAs have similar properties to petroleum derived synthetic plastics like polypropylene (PP) and it is 100% biodegradable in environment (Singh et al, 2015;Sharma et al, 2020). Bacteria belonging to a number of genus are reported to have PHA producing abilities.…”

Section: Introductionmentioning

confidence: 99%

Challenges and Perspectives of Polyhydroxyalkanoate Production From Microalgae/Cyanobacteria and Bacteria as Microbial Factories: An Assessment of Hybrid Biological System

Afreen

Tyagi

Singh

et al. 2021

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

Polyhydroxyalkanoates (PHAs) are the biopolymer of choice if we look for a substitute of petroleum-based non-biodegradable plastics. Microbial production of PHAs as carbon reserves has been studied for decades and PHAs are gaining attention for a wide range of applications in various fields. Still, their uneconomical production is the major concern largely attributed to high cost of organic substrates for PHA producing heterotrophic bacteria. Therefore, microalgae/cyanobacteria, being photoautotrophic, prove to have an edge over heterotrophic bacteria. They have minimal metabolic requirements, such as inorganic nutrients (CO2, N, P, etc.) and light, and they can survive under adverse environmental conditions. PHA production under photoautotrophic conditions has been reported from cyanobacteria, the only candidate among prokaryotes, and few of the eukaryotic microalgae. However, an efficient cultivation system is still required for photoautotrophic PHA production to overcome the limitations associated with (1) stringent management of closed photobioreactors and (2) optimization of monoculture in open pond culture. Thus, a hybrid system is a necessity, involving the participation of microalgae/cyanobacteria and bacteria, i.e., both photoautotrophic and heterotrophic components having mutual interactive benefits for each other under different cultivation regime, e.g., mixotrophic, successive two modules, consortium based, etc. Along with this, further strategies like optimization of culture conditions (N, P, light exposure, CO2 dynamics, etc.), bioengineering, efficient downstream processes, and the application of mathematical/network modeling of metabolic pathways to improve PHA production are the key areas discussed here. Conclusively, this review aims to critically analyze cyanobacteria as PHA producers and proposes economically sustainable production of PHA from microbial autotrophs and heterotrophs in “hybrid biological system.”

show abstract

“…Up to now, Archaea, fungi, several gram-negative and positive bacteria, yeasts, photosynthetic cyanobacteria, and transgenic plants are well known and studied groups reported to produce and store different types of PHB under modified and stressful conditions, but there are few reports of the production of polymers by microalgae species [ 15 , 16 ]. However, microalgae have emerged as potential new producers of polyhydroxybutyrate because they are easy and fast to grow, require a few nutritional quantities to survive, perform photosynthesis by absorbing harmful atmospheric gases, in order to release oxygen, and exhibit a high variability of microalgae species potentially used for the production of biodegradable polymers [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Characterization and Biotechnological Potential of Intracellular Polyhydroxybutyrate by Stigeoclonium sp. B23 Using Cassava Peel as Carbon Source

et al. 2021

View full text Add to dashboard Cite

The possibility of utilizing lignocellulosic agro-industrial waste products such as cassava peel hydrolysate (CPH) as carbon sources for polyhydroxybutyrate (PHB) biosynthesis and characterization by Amazonian microalga Stigeoclonium sp. B23. was investigated. Cassava peel was hydrolyzed to reducing sugars to obtain increased glucose content with 2.56 ± 0.07 mmol/L. Prior to obtaining PHB, Stigeoclonium sp. B23 was grown in BG-11 for characterization and Z8 media for evaluation of PHB nanoparticles’ cytotoxicity in zebrafish embryos. As results, microalga produced the highest amount of dry weight of PHB with 12.16 ± 1.28 (%) in modified Z8 medium, and PHB nanoparticles exerted some toxicity on zebrafish embryos at concentrations of 6.25–100 µg/mL, increased mortality (<35%) and lethality indicators as lack of somite formation (<25%), non-detachment of tail, and lack of heartbeat (both <15%). Characterization of PHB by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC), and thermogravimetry (TGA) analysis revealed the polymer obtained from CPH cultivation to be morphologically, thermally, physically, and biologically acceptable and promising for its use as a biomaterial and confirmed the structure of the polymer as PHB. The findings revealed that microalgal PHB from Stigeoclonium sp. B23 was a promising and biologically feasible new option with high commercial value, potential for biomaterial applications, and also suggested the use of cassava peel as an alternative renewable resource of carbon for PHB biosynthesis and the non-use of agro-industrial waste and dumping concerns.

show abstract

Polyhydroxyalkanoate (PHA): Properties and Modifications

Cited by 197 publications

References 51 publications

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition

Challenges and Perspectives of Polyhydroxyalkanoate Production From Microalgae/Cyanobacteria and Bacteria as Microbial Factories: An Assessment of Hybrid Biological System

Characterization and Biotechnological Potential of Intracellular Polyhydroxybutyrate by Stigeoclonium sp. B23 Using Cassava Peel as Carbon Source

Contact Info

Product

Resources

About