Overproduction of poly-β-hydroxybutyrate in Methylosinus trichosporium 11131 as degradable food packaging material utilizing methane

Biological conversion of methane into poly-beta-hydroxybutyrate (PHB) presents a promising strategy for addressing greenhouse gas emissions and plastic pollution. This study presents a novel approach for the production of PHB from methane using Methylosinus trichosporium 11131. The integrated two-phase process involves the generation of high-density methanotrophic biomass in phase I, followed by the enrichment of PHB in phase II using nutritional modulation. Under optimal growth conditions, a biomass titer of 3.82 +/- 0.01 g/L was achieved, and subsequent nitrate starvation led to the accumulation of PHB (41.24 +/- 0.83 % w/w). Further optimization by exposing the cells to excess methane concentration (5% v/v) and nitrate starvation increased the PHB content to 52.42 +/- 1.03% w/w. The scalability of the process was demonstrated in a 5-L stirred tank bioreactor, yielding a PHB concentration of 2.02 +/- 0.04 g/L. The suitability of the extracted PHB as a degradable food packaging material was evaluated by a comprehensive analysis of its thermal, structural, mechanical, physical, and molecular properties. Our results suggest that the PHB obtained from Methylosinus trichosporium 11131 can serve as a promising alternative to petroleum-based plastics due to its superior properties and biodegradability. Overall, this study presents an innovative biotechnological approach for the conversion of methane into a valuable biopolymer and highlights its potential as a sustainable alternative to conventional plastics.

Automated summary

The study presents a novel approach for converting methane into poly-beta-hydroxybutyrate (PHB) using Methylosinus trichosporium 11131. This two-phase process involves generating high-density biomass in phase I and enriching PHB in phase II. Through optimization, a PHB content of 52.42 +/- 1.03% w/w was achieved, and scalability was demonstrated in a 5-L bioreactor. The extracted PHB showed promising properties and biodegradability, suggesting its potential as a sustainable alternative to petroleum-based plastics.