AUTHOR=Hu Zhong-Ting , Huo Weizhong , Chen Yue , Zhang Qiang , Hu Mian , Zheng Weicheng , Shao Yuchao , Pan Zhiyan , Li Xiaonian , Zhao Jun TITLE=Humic Substances Derived From Biomass Waste During Aerobic Composting and Hydrothermal Treatment: A Review JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2022.878686 DOI=10.3389/fbioe.2022.878686 ISSN=2296-4185 ABSTRACT=

Humic substances (HSs) occupy 80% of organic matter in soil and have been widely applied for soil remediation agents, potential battery materials, and adsorbents. Since the HS extraction rate is very low by microbial degradation in nature, artificial humification processes such as aerobic composting (AC) and hydrothermal treatment (HT) have attracted a great deal of attention as the most important strategies in HS production. This article aims to provide a state-of-the-art review on the development of conversion of biomass waste into HSs based on AC and HT for the first time in terms of mechanisms, characteristics of HSs’ molecular structure, and influencing factors. In addition, some differences based on the aforementioned information between AC and HT are reviewed and discussed in the conversion of biomass waste into HSs in a pioneering way. For biomass waste conversion, a feasible strategy on effective humification processes by combining AC with HT is proposed.