Developments of biobased plasticizers for compostable polymers in the green packaging applications: A review

The demand for biobased materials for various end-uses in the bioplastic industry is substantially growing due to increasing awareness of health and environmental concerns, along with the toxicity of synthetic plasticizers such as phthalates. This fact has stimulated new regulations requiring the replacement of synthetic conventional plasticizers, particularly for packaging applications. Biobased plasticizers have recently been considered as essential additives, which may be used during the processing of compostable polymers to enormously boost biobased packaging applications. The development and utilization of biobased plasticizers derived from epoxidized soybean oil, castor oil, cardanol, citrate, and isosorbide have been broadly investigated. The synthesis of biobased plasticizers derived from renewable feedstocks and their impact on packaging material performance have been emphasized. Moreover, the effect of biobased plasticizer concentration, interaction, and compatibility on the polymer properties has been examined. Recent developments have resulted in the replacement of synthetic plasticizers by biobased counterparts. Particularly, this has been the case for some biodegradable thermoplastics-based packaging applications.

Oral Administration of Artemisone for the Treatment of Schistosomiasis: Formulation Challenges and In Vivo Efficacy

Artemisone is an innovative artemisinin derivative with applications in the treatment of malaria, schistosomiasis and other diseases. However, its low aqueous solubility and tendency to degrade after solubilisation limits the translation of this drug into clinical practice. We developed a self-microemulsifying drug delivery system (SMEDDS), which is easy to produce (simple mixing) with a high drug load. In addition to known pharmaceutical excipients (Capmul MCM, Kolliphor HS15, propylene glycol), we identified Polysorb ID 46 as a beneficial new additional excipient. The physicochemical properties were characterized by dynamic light scattering, conductivity measurements, rheology and electron microscopy. High storage stability, even at 30 °C, was achieved. The orally administrated artemisone SMEDDS formulation was highly active in vivo in S. mansoni infected mice. Thorough elimination of the adult worms, their eggs and prevention of the deleterious granuloma formation in the livers of infected mice was observed even at a relatively low dose of the drug. The new formulation has a high potential to accelerate the clinical use of artemisone in schistosomiasis and malaria.

Sustainable Enzymatic Synthesis of a Solketal Ester—Process Optimization and Evaluation of Its Antimicrobial Activity

The present study aims the enzymatic synthesis of solketal palmitate by esterification between solketal and palmitic acid using heptane as solvent. Lipases from Thermomyces lanuginosus (TLL), Candida rugosa type VII (CRL), and Pseudomonas fluorescens (PFL) were immobilized via interfacial activation on rice husk silica functionalized with triethoxy(octyl)silane (Octyl–SiO2) and used as biocatalysts. A loading of 20–22 mg of lipase/g of support was immobilized independently of the studied enzyme. TLL–Octyl–SiO2 was the most active biocatalyst in oil hydrolysis (656.0 ± 23.9 U/g) and ester synthesis (productivity of 6.8 mmol/min.gbiocat), and it has been chosen for further ester synthesis optimization. The effect of some important parameters such as biocatalyst concentration, reaction temperature and acid:alcohol molar ratio on the reaction has been evaluated using a central composite rotatable design at fixed mechanical stirring (240 rpm) and reaction time (15 min). Subsequently, the effect of reactants concentration and molecular sieve concentration has also been examined. Under optimal conditions (56 °C, acid:alcohol molar ratio of 1:3 with a palmitic acid concentration of 1 M, and 20% wt. of TLL–Octyl–SiO2 per volume of reaction mixture), 83% acid conversion was obtained after 150 min of reaction. The biocatalyst retained 87% of its initial activity after seven successive reaction batches. The product was identified by nuclear magnetic resonance analysis. Antimicrobial activity studies showed that the synthesized ester demonstrated antifungal activity against Candida albicans and Candida parapsilosis, with minimum inhibitory concentration (MIC) between 200 and 400 µg/mL, and bacteriostatic/fungistatic action—minimum microbicial concentration (MMC) > 400 µg/mL.

Lipase immobilization on high water adsorbing capacity bagasse: applications in bio-based plasticizer synthesis

This study investigates the structure and water adsorbing capacity of bagasse and of sodium hydroxide pretreated bagasse. The structures of bagasse and bagasse-NaOH were compared by SEM and XRD. Candida antarctica lipase B was then immobilized on bagasse, bagasse-NaOH and DPA@bagasse-NaOH. The expressed activity and immobilization yield of lipase immobilized on bagasse-NaOH (1.0%) was 36% and 45% higher than that on bagasse. When dopamine (DPA) was used as cationic polymer monomer via self-polymerization for mediating immobilization, the protein loading amounts and activity of lipase immobilized on DPA@bagasse-NaOH were higher than that of bagasse-NaOH. When the DPA concentration was 100 mg/ml, the immobilized lipase expressed activity reached its highest value (800 U/g), where the immobilization yield achieved 96.8%, which was 3.93-fold of lipase immobilized on native bagasse (24.6%). Then the immobilized lipases were used to synthesize a bio-based plasticizer. Lipase immobilized on DPA@bagasse-NaOH exhibited a significantly improved operational stability. Even after 12 batches, a high ester yield (84.2%) was maintained. Additionally, poly (vinyl chloride) PVC blends plasticized with methyl oleate as a secondary plasticizer were investigated. It was discovered that methyl oleate can be used as an effective bio-based plasticizer for PVC. These results indicate that bagasse with high water adsorbing capacity and self-polymerized DPA layer could create a favorable microenvironment for bio-based plasticizer synthesis in esterification reactions.

Environmentally-friendly strategy for separation of 1,3-propanediol using biocatalytic conversion

Glycerol waste from the biodiesel production can be used as a carbon source in the production of 1,3-propanediol (1,3-PD) through microbial fermentation. However, downstream processing is a major bottleneck that restricts its biological production. Here, we investigated an environmentally-friendly method to enzymatically separate 1,3-PD. The transformation of 1,3-PD to an ester was achieved by exploiting the esterification reaction with fatty acids under lipase catalysis. The reaction efficiency was optimized using different poly-alcohols that were existed in the fermentation broth reacted with a fatty acid. Whereas the 1,3-PD conversion reached 62%, only a 0.06% and 0.08% conversion was reached for 2,3-butanediol and glycerol, illustrating the former's more efficient separation. The recovery efficiency of 1,3-PD was 96%. Finally, 1,3-PD was obtained by lipase-directed ester hydrolysis. Taken together, the bio-catalyzed separation process presented here is a novel and promising method for recovering 1,3-PD.

Design and synthesis of a castor oil based plasticizer containing THEIC and diethyl phosphate groups for the preparation of flame-retardant PVC materials

A fine chemical product based on a castor oil containing THEIC and diethyl phosphate groups (THEIC–MR-phosphate) was designed and synthesized, which was used as a flame retardant plasticizer for preparing PVC materials.

Isosorbide and dimethyl carbonate: a green match

In this review the reactivity of the bio-based platform compounds D-sorbitol and isosorbide with green reagents and solvent dimethyl carbonate (DMC) is reported. Dehydration of D-sorbitol via DMC in the presence of catalytic amounts of base is an efficient and viable process for the preparation of the industrially relevant anhydro sugar isosorbide. This procedure is "chlorine-free", one-pot, environmental friendly and high yielding. The reactivity of isosorbide with DMC is equally interesting as it can lead to the formation of dicarboxymethyl isosorbide, a potential monomer for isosorbide-based polycarbonate, and dimethyl isosorbide, a high boiling green solvent. The peculiar reactivity of isosorbide and the non-toxic properties of DMC represent indeed a green match leading to several industrial appealing potential applications.

Insight into the synthesis of isosorbide diester plasticizer using immobilized lipases

The biosafety isosorbide dicaprylate ester plasticizer was sequential synthesized with different immobilized lipases.