Daiki Maruyama, a second-year student in a master's course at the Graduate School of Science and Engineering, Soka University, wrote an original paper “Enhancement of water hyacinth juice treatment in an anaerobic sequential batch reactor with coffee husk–derived biochar” as a first author, and the paper was accepted by an international research journal "BioEnergy Research"*.

The overgrowth of water hyacinths is one of the global issues. Previous research has shown that anaerobic digestion (methane fermentation), in which the juice of crushed and pressed water hyacinth is decomposed by microorganisms under anaerobic conditions without oxygen, is one of the most appropriate methods for treating water hyacinth. In addition, the addition of biofilm carriers that efficiently retain microorganisms is known to increase the efficiency of anaerobic digestion.
In Maruyama's paper, biochar made from coffee husks, an agricultural waste, was used as a carrier to evaluate the anaerobic digestion performance compared to that of ordinary carriers. The results showed that biochar made from coffee husks can be a sustainable and useful carrier to promote the anaerobic digestion of water hyacinth-compressed juice.

Co-author: Shinichi Akizuki (PhD., Lecturer, Institute of Plankton Eco-engineering, Soka University), Mutsumi Sekine (PhD.Assistant Professor, Faculty of Science and Engineering, Soka University), Akinori Fujita (Graduate from Graduate School of Science and Engineering, Soka University), Nigus Gabbiye Habtu (PhD., Professor, Bahir Dar University Institute of Technology), Shinjiro Sato (PhD., Professor, Faculty of Science and Engineering, Soka University), Tatsuki Toda (PhD., Professor, Faculty of Science and Engineering, Soka University)

* BioEnergy Research is a research journal about feedstock biology research related to biomass, biofuels, bioenergy, biochemicals, and biomaterials. It was first published by Springer Nature in 2008, and the Percentile for Agricultural and Biological Sciences in Scopus is 82%.