Efficient production of polyhydroxybutyrate using lignocellulosic biomass derived from oil palm trunks by the inhibitor-tolerant strain Burkholderia ambifaria E5-3.

Lignocellulosic biomass is a valuable, renewable substrate for the synthesis of polyhydroxybutyrate (PHB), an ecofriendly biopolymer. In this study, bacterial strain E5-3 was isolated from soil in Japan; it was identified as Burkholderia ambifaria strain E5-3 by 16 S rRNA gene sequencing. The strain showed optimal growth at 37 °C with an initial pH of 9. It demonstrated diverse metabolic ability, processing a broad range of carbon substrates, including xylose, glucose, sucrose, glycerol, cellobiose, and, notably, palm oil. Palm oil induced the highest cellular growth, with a PHB content of 65% wt. The strain exhibited inherent tolerance to potential fermentation inhibitors derived from lignocellulosic hydrolysate, withstanding 3 g/L 5-hydroxymethylfurfural and 1.25 g/L acetic acid. Employing a fed-batch fermentation strategy with a combination of glucose, xylose, and cellobiose resulted in PHB production 2.7-times that in traditional batch fermentation. The use of oil palm trunk hydrolysate, without inhibitor pretreatment, in a fed-batch fermentation setup led to significant cell growth with a PHB content of 45% wt, equivalent to 10 g/L. The physicochemical attributes of xylose-derived PHB produced by strain E5-3 included a molecular weight of 722 kDa, a number-average molecular weight of 191 kDa, and a polydispersity index of 3.78. The amorphous structure of this PHB displayed a glass transition temperature of 4.59 °C, while its crystalline counterpart had a melting point of 171.03 °C. This research highlights the potential of lignocellulosic feedstocks, especially oil palm trunk hydrolysate, for PHB production through fed-batch fermentation by B. ambifaria strain E5-3, which has high inhibitor tolerance.

Lipase-catalyzed solvent-free synthesis of monoglycerides from biodiesel-derived crude glycerol: Optimized using response surface methodology.

The growth of the biodiesel industry has resulted in significant quantity of crude glycerol. It is necessary to explore the synthesis of high-value-added products from crude glycerol. In this study, the enzymatic synthesis of monoglycerides under solvent-free conditions, employing crude glycerol as the primary feedstock, had been investigated. The analysis showed that the highest yield of monoglycerides was obtained after 12 h, and Novozym 435 showed the highest monoglyceride yield of 18.41 % among the three lipases tested, followed by Lipozyme TL IM and Lipozyme RM IM. Monoglycerides were synthesized from biodiesel-derived crude glycerol using Novozym 435 as the catalyst under solvent-free conditions at different parameters, which were catalyst concentration, substrate molar ratio, and temperature. The yield of monoglycerides was examined in single-factor experiments. Response surface methodology (RSM) was subsequently employed to optimize the synthesis conditions based on the single-factor experimental results. The optimal conditions were at an enzyme concentration of 12.7 wt% and a molar ratio of crude glycerol:oil of 5.7:1 at a reaction temperature of 65.2 °C. The experimental yield of monoglycerides under the optimal conditions was 28.93 %, which is close to the value predicted from the RSM model (29.02 %).

A systematic review on utilization of biodiesel-derived crude glycerol in sustainable polymers preparation.

With the rapid development of biodiesel, biodiesel-derived glycerol has become a promising renewable bioresource. The key to utilizing this bioresource lies in the value-added conversion of crude glycerol. While purifying crude glycerol into a pure form allows for diverse applications, the intricate nature of this process renders it costly and environmentally stressful. Consequently, technology facilitating the direct utilization of unpurified crude glycerol holds significant importance. It has been reported that crude glycerol can be bio-transformed or chemically converted into high-value polymers. These technologies provide cost-effective alternatives for polymer production while contributing to a more sustainable biodiesel industry. This review article describes the global production and quality characteristics of biodiesel-derived glycerol and investigates the influencing factors and treatment of the composition of crude glycerol including water, methanol, soap, matter organic non-glycerol, and ash. Additionally, this review also focused on the advantages and challenges of various technologies for converting crude glycerol into polymers, considering factors such as the compatibility of crude glycerol and the control of unfavorable factors. Lastly, the application prospect and value of crude glycerol conversion were discussed from the aspects of economy and environmental protection. The development of new technologies for the increased use of crude glycerol as a renewable feedstock for polymer production will be facilitated by the findings of this review, while promoting mass market applications.

The Potential Applications of Reinforced Bioplastics in Various Industries: A Review.

The introduction of bioplastics has been an evolution for plastic industry since conventional plastics have been claimed to cause several environmental issues. Apart from its biodegradability, one of the advantages can be identified of using bioplastic is that they are produced by renewal resources as the raw materials for synthesis. Nevertheless, bioplastics can be classified into two types, which are biodegradable and non-biodegradable, depending on the type of plastic that is produced. Although some of the bioplastics are non-biodegradable, the usage of biomass in synthesising the bioplastics helps in preserving non-renewable resources, which are petrochemical, in producing conventional plastics. However, the mechanical strength of bioplastic still has room for improvement as compared to conventional plastics, which is believed to limit its application. Ideally, bioplastics need to be reinforced for improving their performance and properties to serve their application. Before 21st century, synthetic reinforcement has been used to reinforce conventional plastic to achieve its desire properties to serve its application, such as glass fiber. Owing to several issues, the trend has been diversified to utilise natural resources as reinforcements. There are several industries that have started to use reinforced bioplastic, and this article focuses on the advantages of using reinforced bioplastic in various industries and its limitations. Therefore, this article aims to study the trend of reinforced bioplastic applications and the potential applications of reinforced bioplastics in various industries.

Recent Advances in the Enzymatic Synthesis of Polyester.

Polyester is a kind of polymer composed of ester bond-linked polybasic acids and polyol. This type of polymer has a wide range of applications in various industries, such as automotive, furniture, coatings, packaging, and biomedical. The traditional process of synthesizing polyester mainly uses metal catalyst polymerization under high-temperature. This condition may have problems with metal residue and undesired side reactions. As an alternative, enzyme-catalyzed polymerization is evolving rapidly due to the metal-free residue, satisfactory biocompatibility, and mild reaction conditions. This article presented the reaction modes of enzyme-catalyzed ring-opening polymerization and enzyme-catalyzed polycondensation and their combinations, respectively. In addition, the article also summarized how lipase-catalyzed the polymerization of polyester, which includes (i) the distinctive features of lipase, (ii) the lipase-catalyzed polymerization and its mechanism, and (iii) the lipase stability under organic solvent and high-temperature conditions. In addition, this article also focused on the advantages and disadvantages of enzyme-catalyzed polyester synthesis under different solvent systems, including organic solvent systems, solvent-free systems, and green solvent systems. The challenges of enzyme optimization and process equipment innovation for further industrialization of enzyme-catalyzed polyester synthesis were also discussed in this article.

Factors Affecting Mechanical Properties of Reinforced Bioplastics: A Review.

The short life cycle and recalcitrant nature of petroleum-based plastics have been associated with plastic waste accumulation due to their composition rather than worldwide overproduction. The drive to replace single-use products has sparked a considerable amount of research work to discover sustainable options for petroleum-based plastics. Bioplastics open up a new horizon in plastics manufacturing operations and industrial sectors because of their low environmental impact, superior biodegradability, and contribution to sustainable goals. Their mechanical properties regarding tensile, flexural, hardness, and impact strength vary substantially. Various attempts have been made to augment their mechanical characteristics and capacities by incorporating reinforcement materials, such as inorganic and lignocellulosic fibres. This review summarizes the research on the properties of bioplastics modified by fibre reinforcement, with a focus on mechanical performance. The mechanical properties of reinforced bioplastics are significantly driven by parameters such as filler type, filler percentage, and aspect ratio. Fibre treatment aims to promote fibre-matrix adhesion by changing their physical, chemical, thermal, and mechanical properties. A general overview of how different filler treatments affect the mechanical properties of the composite is also presented. Lastly, the application of natural fibre-reinforced bioplastics in the automobile, construction, and packaging industries is discussed.

A Review of the Applications and Biodegradation of Polyhydroxyalkanoates and Poly(lactic acid) and Its Composites.

Overconsumption of plastic goods and improper handling of petroleum-derived plastic waste have brought a plethora of negative impacts to the environment, ecosystem and human health due to its recalcitrance to degradation. These drawbacks become the main driving force behind finding biopolymers with the degradable properties. With the advancement in biopolymer research, polyhydroxyalkanoate (PHA) and poly(lacyic acid) (PLA) and its composites have been alluded to as a potential alternative to replace the petrochemical counterpart. This review highlights the current synthesis process and application of PHAs and PLA and its composites for food packaging materials and coatings. These biopolymers can be further ameliorated to enhance their applicability and are discussed by including the current commercially available packaging products. Factors influencing biodegradation are outlined in the latter part of this review. The main aim of this review article is to organize the scattered available information on various aspects of PHAs and PLA, and its composites for packaging application purposes. It is evident from a literature survey of about 140 recently published papers from the past 15 years that PLA and PHA show excellent physical properties as potential food packaging materials.