Phytochemical compounds and plant products that stimulate methanogenic processes of anaerobic fermentation by microorganisms

Abstract

For the first time, phytochemical stimulants that intensify the process of fermentation and increase the methane content in the produced biogas were applied in the technology of obtaining biogas through anaerobic fermentation. The residual marc obtained from distillation of bio-alcohol from non-standardized raw-materials has served as experimental substrate. A series of substances consisting of various derivatives of phytochemical compounds such as flavonoids, tannins, mono-, di and triterpenoids, sterols, triterpene- and sterol- saponins, carotenoids that manifested themselves as more active stimulants of methane production than the diterpenoid sclareol, or triterpenoids squalene and betulinol, all from the terpenic compounds group were tested experimentally. The laboratory experiments that were performed have applied these three compounds to the anaerobic fermentation environment in concentrations varying between 10-5 -10-3% by mass of substrate, which demonstrated an increase of the ratio of fermentation up to 2-3 times and an increase of the methane content from 50-60 up to 80%. Monoterpenoids, while applied in same quantities, have manifested a reduced intensification of anaerobe fermentation. The investigated flavonoids, tannins and saponins applied in similar conditions of testing have caused the reduction of the content of methane in biogas emissions.