Synthesizing value-added products from methane by a new Methylomonas

Area of Science:

• Microbiology
• Biotechnology
• Synthetic Biology

Background:

• Methane and methanol are abundant C1 carbon sources for microbial utilization.
• Methanotrophs offer potential as 'cell factories' for producing chemicals from C1 substrates.
• Developing efficient microbial strains for bioproduct synthesis from C1 compounds is crucial for sustainable industry.

Purpose of the Study:

• To isolate and characterize a methanotrophic bacterium capable of synthesizing valuable bioproducts from C1 substrates.
• To evaluate the performance of the isolated strain in utilizing C1 compounds and producing target molecules.
• To identify and quantify the synthesized bioproducts, including carotenoids and exopolysaccharides.

Main Methods:

• Isolation and identification of methanotrophs using 16S rRNA sequencing.
• Cultivation of the isolated strain (Methylomonas sp. ZR1) in flask and bubble column reactors.
• Analysis of C1 substrate utilization and product synthesis using HPLC-DAD, HPLC-MS/MS, and GC-MS.
• Evaluation of antioxidant activity of carotenoid extracts using the ABTS+ method.

Main Results:

• Methylomonas sp. ZR1 exhibited a maximum specific growth rate of 0.386 h⁻¹ in bubble column reactors and utilized up to 35 g/L methanol.
• The strain naturally synthesizes lycopene (C40 carotenoids) in addition to C30 carotenoids, with extracts showing significant antioxidant activity.
• High yields of exopolysaccharides (EPS) were produced, composed of glucose, mannose, and galactose (1:2:1 ratio).

Conclusions:

• Methylomonas sp. ZR1 demonstrates excellent C1 substrate utilization and is a promising candidate for producing value-added bioproducts.
• The natural synthesis of lycopene by methanotrophs from C1 compounds is significant, expanding their potential applications.
• This study highlights the potential of methanotrophs as sustainable cell factories for diverse bioproducts.