Antimicrobial Materials with Lime Oil and a Poly(3-hydroxyalkanoate) Produced via Valorisation of Sugar Cane Molasses

Abstract

A medium chain-length polyhydroxyalkanoate (PHA) was produced by Pseudomonas mendocina CH50 using a cheap carbon substrate, sugarcane molasses. A PHA yield of 14.2% dry cell weight was achieved. Chemical analysis confirmed that the polymer produced was a medium chain-length PHA, a copolymer of 3-hydroxyoctanoate and 3-hydroxydecanoate, P(3HO-co-3HD). Lime oil, an essential oil with known antimicrobial activity, was used as an additive to P(3HO-co-3HD) to confer antibacterial properties to this biodegradable polymer. The incorporation of lime oil induced a slight decrease in crystallinity of P(3HO-co-3HD) films. The antibacterial properties of lime oil were investigated using ISO 20776 against Staphylococcus aureus 6538P and Escherichia coli 8739, showing a higher activity against the Gram-positive bacteria. The higher activity of the oil against S. aureus 6538P defined the higher efficiency of loaded polymer films against this strain. The effect of storage on the antimicrobial properties of the loaded films was investigated. After one-year storage, the content of lime oil in the films decreased, causing a reduction of the antimicrobial activity of the materials produced. However, the films still possessed antibacterial activity against S. aureus 6538P.

Harnessing Polyhydroxyalkanoates and Pressurized Gyration for Hard and Soft Tissue Engineering

“…Prior to the analysis, polymer samples were methanolysed as described in Basnett et al (2020). 17 Methyl benzoate was used as the internal standard. Methanolysed samples were analyzed using a Varian GC/MS system consisting of a Chrompack CP-3800 gas chromatograph and a Saturn 200 MS/MS block.…”

Silver Nanoparticle-Coated Polyhydroxyalkanoate Based Electrospun Fibers for Wound Dressing Applications

“…The P(3HO- co -3HD) was created within 15 L bioreactors (Applikon Biotechnology, Tewkesbury, UK) containing a 10 L mixture of Pseudomonas mendocina CH50 and 20 g/L glucose. Subsequently, a two-stage batch fermentation was applied such as described in Basnett et al, 2020 [ 51 ]. The production of P(3HB) was carried out with a similar protocol.…”

Electrosprayed Chitin Nanofibril/Electrospun Polyhydroxyalkanoate Fiber Mesh as Functional Nonwoven for Skin Application

“…P(3HO- co -3HD) was produced using Pseudomonas mendocina CH50 using 20 g/L of glucose in 15 L bioreactors, with 10 L working volume (Applikon Biotechnology, Tewkesbury, UK). Batch fermentation was carried out in two stages as described in Basnett et al, 2020 [ 7 ]. P(3HB) was produced using Bacillus subtilis OK2 using glucose at 20 g/L, using the same protocol as P(3HO- co -3HD) production but using a single stage batch fermentation.…”

“…To date, primarily co-polymerization of P(3HB) with 3-hydroxyvalerate (3HV) has been investigated to increase the flexibility of polymer chains [ 2 ]. Other PHAs are under development to achieve tunable mechanical properties, such as the poly(3-hydroxyoctanoate-co-3-hydroxydecanoate) P(3HO- co -3HD [ 7 ]. In tissue engineering, micro/nano fibrous scaffolds have shown the ability to mimic the fibrillar part of the natural extracellular matrix (ECM), which plays a key role in cell migration, adhesion, and colonization [ 1 ].…”