Plastic-induced pollution has recently triggered global environmental, biodiversity, and public health concerns. Plastic micro/nanoparticles suspended in water that are non-recyclable and non-degradable are found in plants, animals, and even human blood, and their remediation represents an emergent societal need. In this study, a highly efficient strategy is reported to remove microplastics by using a sustainable framework derived from fungal mycelium (FM), which has reached a record capacity at 2.49 g g −1 , as it is known. This excellent removal capacity results from both the inherent properties and surface cationization of the FM. First, FM has a loose entanglement and porous structure with extracellular polymeric substances on the surface, which endows FM with the capacity to adsorb microplastics. Second, FM is engineered with 2,3-epoxypropyltrimethylammonium chloride (EPTAC) to enable its positively charged surface, which significantly enhances the adsorption of microplastics. Kinetic analysis and density functional theory reveal that the excellent microplastic removal is attributed to the enhanced electrostatic interaction between microplastics and EPTAC-g-FM. Along with the inherent merits of FM, which are natural, renewable, biodegradable, environmentally friendly, and easy to scale up, FM represents a green, facile, and cost-effective next-generation technology for remediating microplastics in clean water.

As a major measure to handle livestock manure, digestate is the by-product during biogas production in anaerobic fermentation. Digestate can be returned to cropland as a replacement for chemical fertilizer regarding its cost-effectiveness and rich nutrient content. However, the optimal rates of digestate to substitute chemical fertilizer have not been validated academically. A field study on nine treatments of no fertilizer, chemical fertilizer, and digestate at different rates was conducted to investigate the effects of substituting chemical fertilizer with digestate. The results revealed that replacing chemical fertilizer with liquid digestate did not significantly affect the rice growth regarding the maximum number of seedlings, plant height, tiller numbers, spikelets numbers, ear length, the number of grains per spike, and grain yields. However, improvements were found in the maximum number of seedlings, plant height, tiller number spikelet numbers, the area of the second and third backward leaves, grain yields, and quality when liquid and solid digestate were combined. Furthermore, taking the nutrient inputs, rice growth, grain yield, and quality into consideration, applying liquid digestate of 150 t ha−1 and 75 t ha−1 of liquid combined with 15 t ha−1 solid digestate was suggested for rice production at the study venue.

To overcome major limiting factors of microbial processes in anaerobic digestion (AD), metal and metal ions have been extensively studied. However, there is confusion about the effects of metals and metal ions on biomethane productivity in previous research. In this study, Zn and Zn2+ were selected as representatives of metals and metal ions, respectively, to investigate the effects on biomethane productivity. After the metals and metal ions at different concentrations were added to the batch AD experiments under the same mesophilic conditions, a Zn dose of 1 g/L and a Zn2+ dose of 4 mg/L were found to cause the highest biomethane production, respectively. The results indicate that metal (Zn) and metal ion (Zn2+) have different mechanisms to improve AD performance. There may be two possible explanations. To act as conductive materials in interspecies electron transfer (IET), relatively high doses of metals (e.g., 1 g/L of Zn, 10 g/L of Fe) are needed to bridge the electron transfer from syntrophic bacteria to methanogenic archaea in the AD process. As essential mineral nutrients, the AD system requires relatively low doses of metal ions (e.g., 4 mg/L of Zn2+, 5 mg/L of Fe2+) to supplement the component of various enzymes that catalyze anaerobic reactions and transformations. This research will provide clear insight for selecting appropriate amounts of metals or metal ions to enhance biomethane productivity for industrial AD processes.

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