Biological Conversion Process of Methane into Methanol Using Mixed Culture Methanotrophic Bacteria Enriched from Activated Sludge System

Wastewater treatment plants contribute to the global warming phenomena not only by GHG emissions, but also, by consuming enormous amount of fossil fuel based energy. Therefore, methane bio-hydroxylation has attracted the attention as methanol is an efficient substitute for methane (GHG) due to its transportability and higher energy yield. This work is destined to investigate and optimize the factors affecting the microbial activity within methane bio-hydroxylation system using type I methanotrophs enriched from activated sludge system. The optimization resulted in a notable enhancement of the growth kinetics. The attained maximum specific growth rate (max) (0.358 hr-1) and maximum specific methane biodegradation rate (qmax) (0.605 g-CH4,Total/g-DCW/hr-1) were the highest reported in mixed cultures. Furthermore, the maximum methanol productivity achieved is comparable with pure cultures and equal to 211581 mg/L/day. Whereas, methanol concentration of 48521 mg/L was attained which is two times higher than the reported using mixed culture.