Archaeon Haloferax mediterranei produced PHBV from lemon by-products, up to 3.250 g/L in lab culture
Lemon industry by-products served as the carbon source for a halophilic archaeon; the polymer has 27.4% hydroxyvalerate and lower crystallinity than commercial PHBV.
A study in Polymers describes the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by the halophilic archaeon Haloferax mediterranei grown on lemon industry by-products as the carbon source mdpi.com
Polymersmdpi.comOpen source ↗. The resulting polymer, HFX PHBV, was compared with the commercial grade Enmat Y1000 under identical conditions. Nucleating agents were added to it: orotic acid, boron nitride and theobromine.
Fermentation and yield
The authors varied the by-product concentration, inoculum size and C:N:P ratios, then scaled the process up in a 2 L bioreactor. In minimal medium, 11% (v/v) lemon by-product with a 5% (v/v) inoculum gave the highest productivity, 2.127 g/L PHBV. Enriched media raised polymer accumulation to as much as 3.250 g/L.
Properties of the polymer
The two polymers were characterised by NMR, TGA, MFR, DSC, Raman spectroscopy, XRD and DMA. Compared with Enmat Y1000, HFX PHBV showed lower crystallinity, greater flexibility and a hydroxyvalerate content of 27.4%, which the authors link to improved ductility. Among the nucleating agents, orotic acid was the most effective at enhancing crystallisation kinetics.
The authors conclude that the process yields a biopolymer with physicochemical properties competitive with a commercial standard. They present it as an approach to the problems of plastic pollution and food waste mdpi.com
Polymersmdpi.comOpen source ↗.
