Low-rank coals as a resource for humic amendments through microbial transformation

Abstract

The aim of this work was to identify biotechnological alternatives for transforming the coal into simpler compounds in liquid state. An updated bibliographic review related to the use of humified organic matter was done. The documentary analysis showed that humified organic matter in the soil improves its physical and chemical properties, stimulates microbial populations and promotes plant growth and development. Low-evolved coals or low rank coals have been considered a good source of humic substances. Extraction of these substances can be performed by chemical methods or through solubilization of low rank coals using microorganisms. However, the development of an efficient and low-cost technology has not been possible. A natural control of coal transformation may take place in the soil in the same way as the decomposition of lignin.