Biostimulation of anaerobic digestion using nanomaterials for increasing biogas production

Biomass energy, especially biogas production, is a renewable and sustainable form of energy. Biogas is becoming more important due to its environmentally-sound and energy-saving production technologies. The state-of-the-art focuses on the biostimulation of methanogens using nanomaterials which is a hot topic. Therefore, the objectives of this literature review are to introduce and define the uptake mechanism of nanoparticles (NPs) by methanogenic bacteria, review the enhancement of biogas and methane production using chemical additives such as trace elements and nanomaterials, discuss the biostimulating effects nanoparticles, review the anaerobic digestion of biomass, investigate the recommended concentrations of trace elements and nanoparticles in anaerobic digesters, present the role of some essential trace elements in various enzymes involved in anaerobic digestion, study the free metal mass transport and the metal adsorption to the microorganism surface as well as the metal transport into the microorganism and its biological response. It was found that the nanoparticles (NPs) biostimulate the bacterial cells which results in tremendously enhancing the bacterial activity and the kinetics of bacterial growth and cell division. [GRAPHICS] .