Conventional Petroleum-based Plastics Research Articles

A Review of Polyhydroxyalkanoates: Characterization, Production, and Application from Waste

The search for alternatives to petrochemical plastics has intensified, with increasing attention being directed toward bio-based polymers (bioplastics), which are considered healthier and more environmentally friendly options. In this review, a comprehensive overview of polyhydroxyalkanoates (PHAs) is provided, including their characterization, applications, and the mechanisms underlying their biosynthesis. PHAs are natural polyesters produced by a wide range of prokaryotic and some eukaryotic organisms, positioning them as a significant and widely studied type of bioplastic. Various strategies for the production of PHAs from agroindustrial waste, such as cacao shells, cheese whey, wine, wood, and beet molasses, are reviewed, emphasizing their potential as sustainable feedstocks. Industrial production processes for PHAs, including the complexities associated with extraction and purification, are also examined. Although the use of waste materials offers promise in reducing costs and environmental impact, challenges remain in optimizing these processes to enhance efficiency and cost-effectiveness. The need for continued research and development to improve the sustainability and economic viability of PHA production is emphasized, positioning PHAs as a viable and eco-friendly alternative to conventional petroleum-based plastics.

Bioplastic Production Using Aloe vera Gel as Plasticizer: A Sustainable Approach

The utilization of bioplastics has garnered considerable interest because of their capacity to alleviate environmental issues related to conventional petroleum-based plastics. This study explores the feasibility of utilizing Aloe vera gel as a plasticizer in bioplastic production, aiming to enhance biodegradability and sustainability. Aloe vera gel, a natural polysaccharide-rich material, offers promising characteristics such as biocompatibility, non-toxicity, and abundant availability. This research involves the formulation of bioplastic blends comprising biodegradable polymers such as starch from Cassava, along with varying concentrations of Aloe vera gel as a plasticizer. The resulting bioplastics' mechanical, thermal, and biodegradation properties are systematically evaluated using standard testing methods. Preliminary results demonstrate that Aloe vera gel effectively improves the flexibility and processability of bioplastic materials while maintaining adequate mechanical strength. Thermal analysis reveals enhanced thermal stability in some formulations, indicating the potential for diverse applications. The bioplastic film had a tensile strength of determined to be 5.53 N. Additionally, the percent mean breaking elongation was found to be 1.2%, indicating the extent to which the film can stretch before reaching its breaking point. The thickness yields a result of 0.05 mm. Moreover, biodegradation studies indicate accelerated degradation rates in composting conditions, highlighting the eco- friendly nature of Aloe vera-based bioplastics. This research underscores the possibility of Aloe vera gel as a sustainable alternative plasticizer in bioplastic production, offering a promising avenue for reducing reliance on fossil-based materials and addressing environmental concerns associated with plastic waste pollution.

Alginate-based active and intelligent packaging: Preparation, properties, and applications

Alginate-based packaging materials have emerged as promising alternatives to conventional petroleum-based plastics due to their biodegradability, renewability, and versatile functionalities. This review provides a comprehensive analysis of the recent advances in the development and application of alginate-based films and coatings for food packaging. The composition and fabrication methods of alginate-based packaging materials are discussed, highlighting the incorporation of various functional compounds to enhance their physicochemical properties. The mechanisms of action and the factors influencing the release and migration of active compounds from the alginate matrix are explored. The application of alginate-based packaging materials for the preservation of various food products, including meat, fish, dairy, fruits, and vegetables, is reviewed, demonstrating their effectiveness in extending shelf-life and maintaining quality. The development of alginate-based pH-sensitive indicators for intelligent food packaging is also discussed, focusing on the colorimetric response of natural pigments to spoilage-related pH changes. Furthermore, the review highlights the challenges and future perspectives of alginate-based packaging materials, emphasizing the need for novel strategies to improve their performance, sustainability, and industrial adoption.

3D Printing and Biodegradable Polymers

Abstract 3D printing technology has a wide range of applications in many industries, including automotive, aerospace, biomedical, electronics and packaging, requiring different types of filaments to be used in producing 3D printed objects. The most commonly used materials are metals, ceramics, composites and plastics of which the latter are most available. Since it is necessary to reduce pollution caused by waste from conventional petroleum-based plastics, biodegradable polymers made from renewable resources or produced synthetically have gained in importance recently. Polylactic acid, poly(butylene succinate), thermoplastic starch, poly(butylene adipate co-terephthalate) and polycaprolactone are well-known representatives of this group of materials. They possess desirable properties for 3D printing which make them promising materials in many areas of applications.

Unveiling the emerging trends of egg components-based biodegradable food packaging development: A comprehensive review.

Food packaging plays a crucial role in the food supply chain by aiding in food preservation and reducing food losses throughout the distribution process. The extensive, unregulated utilization, and waste mismanagement of food packaging materials made up of conventional petroleum-based plastics has led to a significant environmental crisis. Egg components-based food packaging has attracted considerable attention from the global packaging industry as a viable alternative to synthetic polymers due to its biodegradability, sustainability, and health-related benefits. This comprehensive review explores the composition and properties of egg components (eggshell, eggshell membrane, egg white, and egg yolk), and recent advancements in biodegradable packaging films derived from them. Additionally, it introduces the characteristics of these films and their applications in food, highlighting their biodegradability, sustainability, and suitable mechanical, barrier, thermal, optical, antioxidant, and antimicrobial properties as substitutes for traditional synthetic polymers. The utilization of various egg components in the packaging industry is a safe, non-toxic, cost-effective, and economical approach. However, it was found that incorporating active compounds from natural sources into packaging films, as well as composite films composed of egg components combined with other biopolymers, resulted in superior properties, compared to single component films. Moreover, the application of novel technologies in film development has proven to be more effective than conventional methods. These innovative egg components-based packaging films can be optimized and commercialized for use as packaging materials for food products.

Ocean Plastics: Extraction, Characterization and Utilization of Macroalgae Biopolymers for Packaging Applications

This review details the extraction, characterization and utilization of seaweed-derived biopolymers for future packaging applications. The review is contextualized within the broader scope of the challenge of plastic pollution and the current urgent need for more sustainable packaging materials. Macroalgae (or seaweed) has been highlighted as a promising source of biopolymers, most commonly sodium alginate, agar and carrageenan, for reasons such as a rapid growth rate and decreased environmental impact when compared with terrestrial plant life. Extraction methods detailed include traditional solvent-based extraction and more sustainable developments such as ultrasound-assisted extraction, microwave-assisted extraction and bead milling. This review additionally presents the characterization techniques most pertinent in determining the applicability of these biopolymers in packaging applications. Properties of key importance to the development of sustainable packaging materials such as thermal properties, mechanical strength, barrier properties and biodegradability are highlighted in comparison to conventional petroleum-based plastics. This review concludes by realistically identifying the challenges faced by implementing seaweed-based biopolymers into packaging structures, such as cost-effectiveness, scalability and performance while suggesting future directions to mitigate these issues and improve the commercial viability of these materials for the packaging industry.

Insight into the fate of bioplastic and similar plant-based material debris in aquatic environments via continuous monitoring of their leachate composition – Release of carbon, metals, and additives

Currently, the environmental problems associated with plastic production and waste, such as the consequences of worldwide pollution of natural waters with microplastics, have led to the seeking of alternative materials that can at least partially replace conventional petroleum-based plastics. Substitute materials include bioplastics and similar plant-based materials or their composites. However, their fate when disposed of in unintended environments (e.g., water bodies) remains largely unknown, while such information is highly desirable prior to massive expansion of exploiting such materials. This study aims to contribute filling this knowledge gap. Specifically, 19 different types of bioplastic and similar plant-based material debris (corresponding to the size of microplastics) were kept in long-term contact with water to mimic their behaviour as water pollutants, and the leachates were continuously analysed. Eighteen of the 19 investigated materials released significant amounts of dissolved organic carbon—up to 34.0 mg per g of debris after 12 weeks of leaching. Each leachate also contained one or more of the following elements: Al, B, Ba, Ca, Fe, K, Mg, Mn, N, Na, P, Si, Ti, and Zn. Non-targeted analysis aimed at providing more specific insight into the leachate composition tentatively revealed 91 individual chemicals, mostly fatty acids and other carboxylic acids, phthalates, terephthalates, adipates, phenols, amides, alcohols, or organophosphates. Based on the compound characteristics, they might be additives, non-intentionally added substances, as well as their degradation products. In general, the current results imply that bioplastics and similar plant-based materials should be considered complex materials that undergo industrial processing and comprise additives rather than harmless natural matter. Additionally, various compounds can release from the bioplastic and similar plant-based material debris when deposited in water. It might have consequences on the fluxes of carbon, metals and specific organic contaminants, and it resembles some properties of conventional petroleum-based microplastics.

A novel approach for poly(hydroxybutyrate-co-hydroxyvalerate) production from vegetable wastes and pig manure: Potential in economy, environment and sustainability

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a promising alternative to conventional petroleum-based plastics, owing to its considerable biodegradability and physicochemical properties. However, the high raw material costs limit its large-scale production. This study established a novel integrated process by coupling the anaerobic fermentation of vegetable wastes (VW) and pig manure (PM) with PHBV biosynthesis. The results demonstrated appreciable PHBV yields of 0.326 and 0.261 gPHBV/gVFA for VW and PM, respectively. Considering the magnitude of VM and PM in China, this novel approach could result in CO2 emission reduction by up to 12.70 million tons per year, as indicated by environmental impact assessment. Additionally, a preliminary economic analysis suggested economic benefits of up to 9.81 billion USD per year. These findings demonstrate that this integrated process can play a significant role in enabling large-scale production of PHBV while simultaneously resolving environmental pollution related problems associated with conventional plastics.

Degradation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Reinforced with Regenerated Cellulose Fibers.

PHBV is a promising plastic for replacing conventional petroleum-based plastics in the future. However, the mechanical properties of PHBV are too low for use in high-stress applications and the degradation of the polymer limits possible applications. In this work, the mechanical properties were, therefore, increased using bio-based regenerated cellulose fibers and degradation processes of the PHBV-RCF composites were detected in accelerated aging tests under various environmental conditions. Mechanical, optical, rheological and thermal analysis methods were used for this characterization. The fibers significantly increased the mechanical properties, in particular the impact strength. Different degradation mechanisms were identified. UV radiation caused the test specimens to fade significantly, but no reduction in mechanical properties was observed. After storage in water and in aqueous solutions, the mechanical properties of the compounds were significantly reduced. The reason for this was assumed to be hydrolytic degradation catalyzed by higher temperatures. The hydrolytic degradation of PHBV was mainly caused by erosion from the test specimen surface. By exposing the regenerated cellulose fibers, this effect could now also be visually verified. For the use of regenerated cellulose fiber-reinforced PHBV in more durable applications, the aging mechanisms that occur must be prevented in the future through the use of stabilizers.

Preparation and property analysis of extruded blown Guar gum based PBAT/PLA composite film: Approach towards sustainable packaging

The study on sustainable packaging led to the development of numerous compostable polymer components for ecofriendly packaging applications. As a promising biodegradable packaging material, this study was done to evaluate the manufacture and characteristics of Guar gum/PLA/PBAT composite films via two-step extrusion procedure, Guar gum, polylactic acid (PLA), and polybutylene adipate terephthalate (PBAT) were used as the matrix ingredients to create the composite films. The impact of Guar gum content on the composite films were assessed with the help of physical, mechanical, and barrier characteristics. The findings demonstrated that with incorporation of Guar gum in the composite film increases the tensile strength upto 153.06 % while preserving their biodegradability behaviour. The developed composite films exhibit good hydrophobicity as shown by contact angle of 89.55° also decrease in water vapour permeability 26.49 gm/m2 when PLA content was increased. The composite films also demonstrated improved thermal stability up to 200 °C. The current study suggest that Guar gum/PBAT/PLA composite films have intact its compostability with enhanced mechanical and barrier qualities giving an opportunity to substitute conventional petroleum-based plastic packaging.

Continuous co-digestion of sewage sludge and highly concentrated waste bioplastic hydrolyzate without shortening hydraulic retention time

Bioplastics have garnered substantial interest as alternatives to conventional petroleum-based plastics. However, their management and conversion to biogas continues to be significantly challenging. In this study, we evaluated the suitability of various plastics for hydrolysis at 160 °C for 12 h using different solvents. The biogas yield (BGY) of the monomers constituting these plastics and the obtained plastic hydrolyzates was comprehensively evaluated. When water was used as a solvent, 100 % hydrolysis of polylactic acid (PLA) and polybutylene succinate (PBS) was observed. When polybutylene adipate co-terephthalate (PBAT) and polyhydroxybutyrate (PHB) were hydrolyzed with water, the degradation ratio was approximately 30 %; however, using an aqueous lactic acid solution as a solvent improved the degradation ratio to 78 % and 100 %, respectively. In the BGY test of the plastic hydrolyzates, the biogas volumes derived from the hydrolyzates were 563, 461, 337, and 573 mL/g COD-added for PLA, PBS, PBAT, and PHB, respectively. With 1,160 gCOD/L waste PLA hydrolyzate, continuous co-digestion of sewage sludge and the hydrolyzate was conducted. Organic loading rates of sewage sludge and the hydrolyzate were 2.3 and 2.4 gCOD/L/d, respectively. The operation was stable and the methane production volume from the PLA hydrolyzate was 414 L/kgCOD-added. Using highly concentrated PLA hydrolyzate, the hydraulic retention time was 19.3 days, which was only 0.7 days shorter than that of anaerobic digestion of sewage sludge only (20 days). Therefore, highly concentrated PLA hydrolyzate maintains the retention time of normal sewage sludge digestion. Conclusively, the present study has crucial practical implications for plastic waste management.

Novel biopolymeric materials potential utilization for environmental practices

Significant current trending research explored in this article aims to provide a comprehensive analysis of the materials manufacturing processes involved in the utilization of environmentally friendly biopolymers for industrial practices. Biopolymers are gaining significant attention as sustainable alternatives to conventional petroleum-based plastics due to their renewable nature and reduced environmental impact. This manuscript aims to identify the different types of biopolymers used in industrial applications, their manufacturing techniques, and their potential benefits and challenges. It also explores the current state of research in this field and outlines future directions for advancements in biopolymer manufacturing. The rapid growth of environmental practices has led to an alarming increase in pollution and environmental degradation. To tackle this issue, researchers and industries have been exploring the utilization of biopolymers as a sustainable alternative to traditional materials. Biopolymers, derived from renewable sources such as plants, animals, and microorganisms, offer numerous advantages such as reduced carbon footprint, biodegradability, and non-toxicity. This article aims to provide a comprehensive studies of the materials manufacturing process of environmentally friendly biopolymers and their industrial applications.

Biofilm of petroleum-based and bio-based microplastics in seawater in response to Zn(II): Biofilm formation, community structure, and microbial function

Microplastic biofilms are novel vectors for the transport and spread of pathogenic and drug-resistant bacteria. With the increasing use of bio-based plastics, there is an urgent need to investigate the microbial colonization characteristics of these materials in seawater, particularly in comparison with conventional petroleum-based plastics. Furthermore, the effect of co-occurring contaminants, such as heavy metals, on the formation of microplastic biofilms and bacterial communities remains unclear. In this study, we compared the biofilm bacterial community structure of petroleum-based polyethylene (PE) and bio-based polylactic acid (PLA) in seawater under the influence of zinc ions (Zn2+). Our findings indicate that the biofilm on PLA microplastics in the late stage was impeded by the formation of a mildly acidic microenvironment resulting from the hydrolysis of the ester group on PLA. The PE surface had higher bacterial abundance and diversity, with a more intricate symbiotic pattern. The bacterial structures on the two types of microplastics were different; PE was more conducive to the colonization of anaerobic bacteria, whereas PLA was more favorable for the colonization of aerobic and acid-tolerant species. Furthermore, Zn increased the proportion of the dominant genera that could utilize microplastics as a carbon source, such as Alcanivorax and Nitratireductor. PLA had a greater propensity to harbor and disseminate pathogenic and drug-resistant bacteria, and Zn promoted the enrichment and spread of harmful bacteria such as, Pseudomonas and Clostridioides. Therefore, further research is essential to fully understand the potential environmental effects of bio-based microplastics and the role of heavy metals in the dynamics of bacterial colonization.

Cradle-to-gate life cycle assessment of Spirulina bioplastic produced via plasticization with glycerol

Bioplastics have been used as alternatives to conventional petroleum-based plastics to lessen the burdens on marine and terrestrial environments due to their non-biodegradability and toxicity. However, recent studies have shown that not all bioplastics may be environmentally friendly. Microalgae, such as Spirulina that do not require arable land, have been identified as a potential bioplastic source. In this study, cradle-to-gate life cycle assessment (LCA) was carried out in openLCA program using the Agribalyse database, to evaluate the environmental impacts of Spirulina bioplastic, formed from plasticization of Spirulina powder with glycerol. Two processes were created for the inventories of (i) Spirulina powder and (ii) Spirulina bioplastic, where the output of the former served as an input for the latter. The extruded bioplastic sheets were food-grade and could be used as edible packaging materials. The bioplastic was also compared to conventional plastics and it was found that the energy consumption was 3.83 ± 0.26 MJ/kg-bioplastic, which was 12% and 22% higher than that of LDPE and PVC plastic films, respectively. The impacts on the environment showed that the chemical growth medium (Zarrouk medium) and electricity were the main contributors in most of the categories. Compared to the PVC and LDPE films, the Spirulina bioplastic's impacts on the aquatic ecosystems were 2–3 times higher. The global warming potential of the Spirulina bioplastic was 1.99 ± 0.014 kg CO2 eq, which was 23% and 47% lower than that of LDPE and PVC films, respectively. Sensitivity analysis was carried out by changing the electricity source and using alternative growth media. Except for the case of switching to solar energy, the results for other cases did not differ significantly from the base case scenario. Future studies were suggested to identify different greener alternatives to the growth medium as well as different energy mixes for more environmentally benign solutions.

Consistently inconsistent: The false promise of ‘sustainable’ plastics

Abstract This perspective explains why the lack of regulation around bioplastics remains a hurdle for the successful development and implementation of a legally binding agreement (the Global Plastics Treaty) by the United Nations Environment Assembly to curb plastic pollution by 2024. For example, bioplastics have been marketed to consumers as the panacea solution to our plastic waste crisis. Of the >400 million tonnes of plastics produced each year, <1% are bioplastics, but the market value of bioplastics is expected to grow. The rapid growth of the environmentally ‘sustainable’ plastic market has resulted in an overwhelming variety of products with different properties and labels, which has led to widespread public confusion, particularly about disposal guidelines. The umbrella term of ‘bioplastics’ describes plastics that can be fully or partially sourced from biological matter, unlike conventional petroleum-based plastics. Within this family of plastics, products can be ‘biodegradable’, ‘oxo-biodegradable’ and ‘compostable’ depending on their chemical composition and the external conditions required at disposal (end-of-life). However, cases of petroleum-based biodegradable plastics have been referred to as bioplastics, which is inaccurate. Overall, this lack of regulation remains a hurdle for the successful development and implementation of the Global Plastics Treaty.

From Hemp Waste to Bioactive Nanofiber Composites: Deep Eutectic Solvents and Electrospinning in Upcycling Endeavors.

Natural fibers have attracted increasing interest as an alternative to produce environmentally friendly and sustainable materials. Particularly, hemp fibers have been widely used in various industrial applications due to their extremely unique properties. However, hemp can generate a large amount of agro-waste, and it results in an attractive source of biopolymers for the development of low-cost materials as an alternative to the raw materials and conventional petroleum-based plastics. In addition, deep eutectic solvents (DESs), a new type of truly green solvents, have been shown to remove gums, lignin, and other non-cellulosic components from hemp fibers. Reusing these components dissolved into the DESs to fabricate new materials directly by electrospinning is a very attractive but still unexplored endeavor. Thus, this innovative research to venture new upcycling pathways is focused on the fabrication of composite nanofibers by electrospinning of a gel-based blend of Poly(vinyl alcohol) (PVA) and hemp agro-waste (HW) dissolved into choline chloride (ChCl):Glycerol (1:2) and ChCl:Urea (1:2) DES mixtures. The results obtained revealed that the produced nanofibers displayed uniform appearance with diameters ranging from 257.7 ± 65.6 nm to 380.8 ± 134.0 nm. In addition, the mechanical properties of the electrospun composite nanofibers produced from the gel-based blends of HW dissolved in DESs and PVA (HW-DESs_PVA) were found to be superior, resulting in an enhanced tensile strength and Young's modulus. Furthermore, the incorporation of HW into the nanofibers was able to provide bioactive antioxidant and antibacterial properties. Overall, this study demonstrated a promising, more sustainable, and eco-friendly way to produce electrospun composite nanofibers using HW in a circular economy perspective.

Enhancing poly(3-hydroxybutyrate) production in halophilic bacteria through improved salt tolerance

Polyhydroxyalkanoates (PHA) have emerged as a promising bio-compound in the industrial application due to their potential to replace conventional petroleum-based plastics with sustainable bioplastics. This study focuses on Halomonas sp. YJPS3-3, a halophilic bacterium, and presents a novel approach to enhance PHA production by exploiting its salt tolerance toward PHA biosynthesis. Through gamma irradiation-induced mutants with enhanced salt tolerance from 15% NaCl to 20% NaCl, mutant halo6 showing a significant 11% increase in PHA yield, was achieved. Moreover, the mutants displayed not only higher PHA content but also remarkable cell morphology with elongation. In addition, this research unravels the genetic determinants behind the elevated PHA content and identifies a corresponding shift in fatty acid composition favoring PHA accumulation. This novel mutant obtained from gamma irradiation with enhanced salt tolerance in halophilic bacteria opens up new avenues not only for the bioplastic industry but also for applications in the production of high-value metabolites.

Enhancing Microalgae Content in Biocomposites through a Mechanical Grinding Method.

Microalgae-based biocomposites are gaining traction as ecofriendly and cost-effective alternatives to conventional petroleum-based plastics. However, achieving a homogeneous dispersion of microalgae within a biocomposite matrix remains a challenge. In this study, we investigated the effect of the size of dried microalgae (Chlorella sp.) on the quality of biocomposites. Ball milling, a mechanical grinding process, was used to control the size of the pretreated dried microalgae. Our results demonstrate that the microalgae size strongly depends on the total weight of the stainless-steel balls, rather than the number of balls used in the milling process. Poly(ethylene-vinyl acetate) (EVA), with functional groups resembling those of Chlorella sp., was incorporated into the ball-milled microalgae to produce homogeneous biocomposites. Smaller Chlorella sp. particles improved the ratio of microalgae and the mechanical properties of the biocomposites. Dried Chlorella sp. particles up to 161.43 μm, which were 72.84% smaller than the untreated microalgae, were obtained after 6 h of ball milling using 3/8-inch balls. This enabled the production of biocomposites with 60 wt.% microalgae and 61.02% of the tensile strength of pure EVA, comparable to traditional polymers. Our findings suggest that controlling the microalgae size through ball milling can improve the quality of microalgae-based biocomposites.

Polylactic acid films reinforced with chitin nanocrystals: Biodegradation and migration behavior

Polylactic acid (PLA) is a widely recognized sustainable alternative to conventional petroleum-based plastics for food packaging. To enhance its properties that currently trail those of conventional packaging materials, the addition of chitin nanocrystals (ChNC) has been considered. This has led, amongst others to stronger materials. For their ultimate application, it is also important to evaluate these materials in terms of food safety and environmental impact. In this study, we investigate the biodegradation of and migration from ChNC/PLA nanocomposites. The solution casting method was used to prepare PLA and ChNC/PLA nanocomposites, and overall migration (OM) tests were carried out with food simulants (10 % ethanol and isooctane). Additionally, we evaluated the biodegradability (crude chitin powder, ChNC, and nanocomposites) based on ISO norm no 14851:2019. The OM tests demonstrated that the migration levels from ChNC-PLA composites were below the allowed limit (60 mg/kg). The biodegradability of ChNC was comparable to that of crude chitin powder and microcrystalline cellulose, and interestingly, when incorporated in PLA films did not impact the biodegradability of PLA in a negative way. In summary, the migration and biodegradation of ChNC/PLA nanocomposites exhibit encouraging potential for their future utilization in food packaging.

Soft sensor based on Raman spectroscopy for the in-line monitoring of metabolites and polymer quality in the biomanufacturing of polyhydroxyalkanoates.

Polyhydroxyalkanoates (PHA) are among the most promising bio-based alternatives to conventional petroleum-based plastics. These biodegradable polyesters can in fact be produced by fermentation from bacteria like Cupriavidus necator, thus reducing the environmental footprint of the manufacturing process. However, ensuring consistent product quality attributes is a major challenge of biomanufacturing. To address this issue, the implementation of real-time monitoring tools is essential to increase process understanding, enable a prompt response to possible process deviations and realize on-line process optimization. In this work, a soft sensor based on in situ Raman spectroscopy was developed and applied to the in-line monitoring of PHA biomanufacturing. This strategy allows the collection of quantitative information directly from the culture broth, without the need for sampling, and at high frequency. In fact, through an optimized multivariate data analysis pipeline, this soft sensor allows monitoring cell dry weight, as well as carbon and nitrogen source concentrations with root mean squared errors (RMSE) equal to 3.71, 7 and 0.03 g/L, respectively. In addition, this tool allows the in-line monitoring of intracellular PHA accumulation, with an RMSE of 14 gPHA/gCells. For the first time, also the number and weight average molecular weights of the polymer produced could be monitored, with RMSE of 8.7E4 and 11.6E4 g/mol, respectively. Overall, this work demonstrates the potential of Raman spectroscopy in the in-line monitoring of biotechnology processes, leading to the simultaneous measurement of several process variables in real time without the need of sampling and labor-intensive sample preparations.