Biological Conversion of Methane and Carbon Dioxide into Methanol using Methylosinus Trichosporium NCIMB 11131

Abstract

The emission of greenhouse gases, such as methane and carbon dioxide, has been increasing globally at an alarming rate. Conventional chemical methods to transform methane and carbon dioxide into useful chemicals are plagued by the requirement for expensive catalysts and extreme operating conditions. The exploitation of microorganisms as biocatalysts is an attractive alternative to sequester these greenhouse gases and convert them into value-added chemicals or liquid fuels through their inherent metabolic pathways. Microbial biocatalysts are advantageous over chemical processes as they require mild-operating conditions and do not release any toxic by-products. From a contextual perspective, methanotrophs, a class of Gram-negative, methane oxidizing bacteria, are being explored as novel platform to produce methanol – a potential fuel. Methanotrophs uptake methane as an obligate source for the derivation of carbon and energy. Besides, methanotrophs are capable of capturing carbon dioxide and enzymatically reducing it into methanol under specific conditions. However, the state-of-the-art technology of methanotrophic methanol production is primarily constrained by: (i) low titer of methanotrophic biomass and methanol owing to (ii) limited mass transfer and solubility of methane and CO2 in liquid medium. Current rising energy demand and rapid depletion of non-renewable fossil fuel reserves have shifted the research focus towards exploring non-petroleum based cleaner and renewable alternate transportation fuels. To that end, oxygenated fuels (or alcohols) such as methanol, are advantageous in terms of improving the combustion, emission and performance characteristics of engine. However, a major concern is the dependency of alternative fuel technology on chemical methods for methanol synthesis which are energy-intensive, as well as economically and environmentally non-sustainable. The present study was designed to address the existing challenges and gaps through the development of a sustainable bioprocess for methanol production.