We can send you a cheap powder of nanoparticles, which enhances the decomposition to methane. Write an official letter asking our rector.  All the addresses on the site of our university.

Best regards.

There exists many papers concerning use of nanoparticles to incrtease methane production during anaerobic digestion. Please se the following links:

http://www.sciencedirect.com/science/article/pii/S0960148115304067

http://www.nature.com/articles/srep25857

https://phys.org/news/2014-10-nanoparticle-technology-triples-production-biogas.html

https://www.biogasplus.info/2015/12/28/applied-nanoparticles-to-biogas-production-biogas/

According to my opinion there is not "the best one nanoparticle" because the results depend on many technological parameters of the process and of substrates.

It is important to chose such concentration of nanoparticles added, which is not toxic to microorganisms.

Best regards  Vit.

Thank you Md. Saiful Islam and Vit Mateju