Screening for Methane Utilizing Mixed Communities with High Polyhydroxybutyrate (PHB) Production Capacity Using...

Area of Science:

• Biotechnology
• Environmental Science
• Microbiology

Background:

• Petroleum-based plastics pose environmental risks, increasing interest in bioplastics like polyhydroxyalkanoates (PHA).
• Methanotrophic bacteria can convert methane into polyhydroxybutyrate (PHB), a biodegradable polymer.
• Wastewater treatment plants (WWTPs) offer a sustainable source of methane for biopolymer production.

Purpose of the Study:

• To develop and compare a novel recycling strategy for maximizing polyhydroxybutyrate (PHB) production in methanotrophic bacteria.
• To evaluate the impact of different nitrogen sources (nitrate and ammonia) on PHB accumulation.
• To assess the influence of the recycling strategy on microbial community composition, specifically type II methanotrophs.

Main Methods:

• A new recycling strategy was compared against a conventional approach for PHB production using methanotrophic bacteria.
• Methane gas from WWTPs served as the carbon source and electron donor.
• PHB accumulation, growth rate, methane uptake, and biomass yield were monitored.
• Microbial community analysis was performed using sequencing.

Main Results:

• The new recycling strategy achieved significantly higher PHB accumulation (59.4% with ammonia, 54.3% with nitrate) compared to the conventional setup (37.8% with ammonia, 9.1% with nitrate).
• The proposed method successfully stimulated the growth of PHB-accumulating type II methanotrophs.
• Microbial sequencing confirmed an increased abundance of type II methanotrophs and other PHB producers.

Conclusions:

• The novel recycling strategy is highly effective for enhancing PHB production in mixed methanotrophic cultures.
• This approach offers a promising method for the industrial-scale production of bioplastics from waste-derived methane.
• The technique facilitates the enrichment of desirable PHB-producing microbial populations.