Techniques and mechanisms of bacteria immobilization on biochar for further environmental and agricultural applications.

Bacteria immobilization on biochar is a promising approach to achieve high concentration and stability of microbial cells for several applications. The present review addressed the techniques utilized for bacteria immobilization on biochar, discussing the mechanisms involved in this process, as well as the further utilization in bioremediation and agriculture. This article presents three immobilization techniques, which vary according to their procedures and conditions, including cell growth, adsorption, and adaptation. The mechanisms for cell immobilization are primarily adsorption and biofilm formation on biochar. The favorable characteristics of biochar immobilization depend on the pyrolysis methods, raw materials, and properties of biochar, such as surface area, pore size, pH, zeta potential, hydrophobicity, functional groups, and nutrients. Scanning electron microscope (SEM) and colony forming unit (CFU) are the analyses commonly carried out to verify the efficiency of bacteria immobilization. The benefits of applying biochar-immobilized bacteria include soil decontamination and quality improvement, which can improve plant growth and crop yield. Therefore, this emerging technology represents a promising solution for environmental and agricultural purposes. However, it is important to evaluate the potential adverse impacts on native microbiota by introducing exogenous microorganisms. [Display omitted] • Adsorption concepts explains the mechanisms of bacteria immobilization on biochar. • Biochars pyrolyzed at higher temperatures (> 500 ºC) are preferred for bacteria immobilization. • EPS helps to immobilize bacteria on biochar, reducing the stress caused by contaminants during bioremediation. • The microorganisms able to grow in the presence of contaminants are promising for immobilization. [ABSTRACT FROM AUTHOR]