In a groundbreaking study from Shanghai Tongji University, researchers have discovered a natural and efficient way to tackle polycyclic aromatic hydrocarbons (PAHs), harmful hydrophobic pollutants that are widespread in our environment. The key to this innovative approach lies in mycelial pellets, tiny structures formed by Penicillium thomii ZJJ, a type of fungus.
Penicillium crystallinum - Nomenclature of the genus Penicillium
The live mycelial pellets demonstrated an impressive ability to remove 93.48% of pyrene, a representative PAH, at a concentration of 100 mg/L within just 48 hours. Even when heat-killed, these pellets achieved a noteworthy removal rate of 65.01%. Importantly, the mycelial pellets showed a preference for adsorbing high molecular weight PAHs, which are not only more toxic but also more challenging to eliminate.
The research revealed that the adsorption process of these mycelial pellets is primarily a spontaneous physical adsorption occurring as a monolayer on a uniform surface. Mass transfer emerged as the crucial rate-limiting step, with carboxyl and N-containing groups on the mycelial surface serving as the main adsorption sites.
Extracellular polymeric substances (EPS) produced by the mycelial pellets played a key role in enhancing adsorption, and even heat-killed mycelial pellets coupled with EPS achieved a removal effect similar to that of live ones. The researchers identified electrostatic and hydrophobic interactions as the driving forces behind the five-step adsorption process.
Beyond their impressive adsorption capabilities, the mycelial pellets exhibited high environmental tolerance, effectively removing pyrene across a wide range of pH and salt concentrations. Factors such as pellet diameter and humic acid concentration were found to significantly influence microbial adsorption effects.
In addition to their environmental benefits, a cost-effectiveness analysis revealed that mycelium pellets are a low-cost adsorbent, making them a promising solution for large-scale applications. This research not only deepens our understanding of the adsorption process but also proposes a cost-effective and environmentally friendly method, utilizing heat-killed mycelial pellets combined with EPS, to tackle PAH removal.
In essence, this study highlights the potential of these fungi-derived pellets as a natural and sustainable alternative for the removal of harmful pollutants, offering a glimpse into a cleaner and healthier future for our environment.