Atmospheric concentrations of methane are currentlyincreasing at a rate of one percent annually. Emissions of thisgreenhouse gas from coal mines now amount to about 65 million tonsannually, and are increasing steadily. Methane absorbed ontointernal coal surfaces is released as the coal is mined. This gasis vented to the atmosphere from gob wells or with ventilation air. The methane concentrations are dilute, and recovery is rarelyeconomical. This project involves a novel concept to convertwaste methane into a high value product, single cell protein(SCP) for animal feed. Methanotrophic bacteria convert methaneinto cell mass with a high protein content that has been shown tobe a suitable supplement for protein in animal and poultry diets.The fermentation is aerobic, requiring at least an equal volumeof oxygen with methane; consequently, dilute methane concentrationsare required. Phase I will screen the various methanotrophs toselect those that have the fastest growth rates and highest yieldsof SCP. Continuous culture studies will be conducted with the bestbacteria to define reaction kinetics and minimal reactor volume. The design and economics of a process to produce SCP from coal minemethane will be projected to determine feasibility. Phase II willdefine engineering and marketing parameters for large scaleproduction of SCP. A prototype unit will be constructed andoperated in phase III to demonstrate scale-up.Anticipated Results/Potential Commercial Applications as described by the awardee:There are 180 underground coal mines that discharge large quantities of methane into the atmosphere. The averagedischarge from the ten largest methane emitting mines is 11 millioncubic feet per day. Conversion of the gas from one of these minesinto SCP would generate $30 million annually, requiring nominalcapital and operating cost. Therefore, significant economic andenvironmental incentives exist for commercialization of thetechnology.
