Biofilm formation on abiotic and biotic surfaces was studied with two hyphobacteria, strongly attached to the surface of the arbuscular mycorrhizal fungus (AMF) Rhizoglomus irregulare (Ri) DAOM 197198 and two mycorrhizobacteria, loosely attached to the roots of different mycorrhizal plants. When the sparingly soluble igneous phosphate rock (PR) from Quebec, or when the chemical hydroxyapatite were used as sole phosphorus (P) source, hyphobacteria Rhizobium miluonense Rm3 and Burkholderia anthina Ba8 produced significantly more biofilms than mycorrhizobacteria Rahnella sp. Rs11 and Burkholderia phenazinium Bph12, as indicated by the crystal violet assay or by quantifying biofilm exopolysaccharides. As previously observed with planktonic bacteria, biofilms mobilized P by lowering the pH and releasing gluconic acid. The high efficiency of P mobilization by the hyphobacteria Ba8 was linked to the presence of more viable cells in its biofilm as revealed by the hydrolysis of fluorescein diacetate. Scanning electron microscopy micrographs showed a high adherence of the best P-solubilizer hyphobacteria Ba8 on the surface of Quebec PR. Hydroxyapatite porous structure did not allow a good adherence of Ba8. Ba8 formed an important biofilm on the hyphae of Ri DAOM 197198 with low reactive Quebec PR while no biofilm was observed with the high reactive hydroxyapatite. Results confirm the possible presence of specificity between the Ri DAOM 197198 and the hyphobacteria and suggest that the interaction would be regulated by the availability of P.

Anaerobic digestion (AD) is an environmentally sustainable approach for managing invasive plants species, mitigating pollution, and generating renewable energy. However, the complex structure of these biomasses limits their biodegradability and necessitates pretreatment to enhance methane production. This study explored the biotransformation of two invasive species, Reynoutria japonica and Phragmites australis, harvested across diverse phenological stages. Bioprocess intensification was achieved through a single-stage process using a hydrolytic–methanogenic consortium under thermophilic conditions (55 °C, 25 days). The impact of harvest timing distinct plant fractions (shoot vs. root) on biogas production was meticulously evaluated. Results revealed progressive biogas production. Notably, winter-harvested shoot fractions exhibited the highest methane-rich biogas, achieving 551.12 ± 33.07 mL/g VS for Reynoutria and 401.42 ± 24.09 mL/g VS for Phragmites. The resulting digestate demonstrates a rich composition of essential macronutrients (N-P-K) vital for plant growth, highlighting its potential as a valuable biofertilizer. Significantly, complete inhibition of seed germination was observed, confirming the process’s efficacy in preventing the further propagation of invasive species. This research underscores that thermophilic anaerobic digestion, coupled with hydrolytic treatment, is a significant advancement in the valorization of invasive biomasses, contributing to both renewable energy production and ecological recovery.

Agroforestry residues are a promising source of organic matter and energy. These organic wastes are often poorly managed by incineration or open-air composting, resulting in the emission of greenhouse gases. Solid-state anaerobic digestion has recently attracted considerable attention to converting organic waste with a high total solids content, such as agroforestry residues, into renewable energy. However, the complex structure of these residues is still a defiance to this technology. Their degradation requires a long period, resulting in low heat and mass transfer. In addition, the process is often inhibited by the accumulation of toxic compounds. An efficient management process has remained under development. Comprehending the challenges faced when treating agroforestry waste is necessary to create practical applications. This review provides essential information for more effective management of complex agricultural and forestry residues using the SS-AD process. It covers the different parameters and experiments that have successfully managed these residues for renewable energy production. Various solutions have been identified to overcome the drawbacks encountered. These include co-digestion, which brings together different residues for better sustainability, and the strategies used to improve energy production from these residues at different levels, involving efficient pretreatments and appropriate operational reactor designs.

In the context of the global energy transition, renewable and sustainable resources are increasingly being explored as an alternative to fossil fuels. Lignocellulosic and organic waste biomass is abundant, low-cost, and represents a promising feedstock for bioenergy production. However, the valorization of abandoned or underutilized residues remains largely unexplored. This study evaluated the bioenergy potential of eight solid organic waste materials collected from abandoned sites, including: (1) landfilled woodwaste, (2) softwood and (3) hardwood sawdust, (4) fresh pine bark (5) decomposed pine bark, (6) decomposed leaf and yard waste, (7) decomposed organic food waste (8) and aged barn dust. Physicochemical characterization revealed their high organic matter content across all substrates, with volatile solids (VS) ranging from 40% to 95%, whereas the C/N ratio varied widely from 10 to 1297. To optimize conditions, co-digesting was performed at a fixed substrate-to-inoculum ratio (SIR) at 1, which effectively balanced the high carbon content and enhanced process stability. Under thermophilic anaerobic digestion, organic matter degradation ranged from 16% to 71%. The highest specific methane potential reached 89.9 ± 7.7 L CH₄·kg VS added⁻¹ for fresh pine bark, while the lowest was 25.2 ± 6.8 L CH₄·kg VS added⁻¹ for decomposed organic food waste. The resulting digestates were rich in nutrients, demonstrating high agronomic value. Anaerobic digestion of abandoned lignocellulosic and organic residues presents a dual benefit: it reduces pollution while producing renewable energy in the form of methane and valuable by-products that can be used as fertilizers, thereby ensuring a circular economy. This study demonstrates the significant potential of utilizing overlooked waste streams as valuable resources in sustainable bioenergy generation.