Azolla filiculoides is an aquatic fern with the potential to become a source of raw materials in a biorefinery system, e.g., a source of soluble and insoluble carbohydrates, proteins, carotenoids, and polyphenols. The fiber chemical content was determined as cellulose (19.2% dry basis) and hemicellulose (7.6% dry basis) content. Azolla has no lignin as a cell wall structure material. Cellulase treatment showed no effect in ethanolic extraction, but polyphenols were found in the enzyme solution at the end of the reaction. The phenolic acids and flavonoids contents of those with health promoting activity were determined, with gallic, syringic, rosmarinic, and p-coumaric the most abundant acids; kaempferol, apigenin, and quercetin were the most abundant flavonoids. The results show that A. filiculoides is a valuable source of bioactive components and cellulosic materials.

Trichoderma is a fungus that can degrade cellulose-rich waste using enzymes derived from their cellular metabolism. For its growth, aerated bioreactors are used in submerged culture where oxygen is one of the elements that limits this process. The aim of this study was to characterize the hydrodynamics and mass transfer of an internal flat-plate airlift cylindrical bioreactor for the biodegradation of newspaper using T. reesei as a study model. Hydrodynamics (gas hold-up, mixing time, and the Reynolds number) and mass transfer (kLa) properties were characterized in biphasic (water-air) and triphasic (Trichoderma reesei- minimal basal medium-air) systems. Degradation kinetics of newspaper in the airlift bioreactor in a batch culture were performed. On day 20, the enzyme activities, biomass, residual cellulose, protein concentration and reducing sugars were 1421 IU L-1 CMCase, 8.02 g L-1, 2.19 g L-1, 0.0018 g L-1, 0.07 g L-1 , respectively. Finally, the overall kLa (triphasic system) was calculated to be in the range of 2.34-14.76 h -1 with a Reynolds number of 1757 depending on the hydrodynamic parameters. In addition, the theoretical kLa was compared and estimated with respect to the experimental values with a maximum error of ±20% which is acceptable based on the proposed coefficient of performance. The relationship between mass transfer and the Reynolds number is an important criterion in assessing an optimal degradation of newspaper on an industrial scale.

The rhizosphere is the soil that surrounds, and is influenced by, the roots of a plant. It is considered one of the most complex ecosystems on the planet due to the intense interactions that occur between plants and microorganisms, as well as the competition that occurs among the microbial components. Due to this competition and beneficial interactions, a contribution of paramount relevance occurs in terms of chemical, physical, and biological characteristics that allow the plant and crop development. To mitigate ecosystem disturbances, it is necessary to compensate the imbalance of these conditions. Unfortunately, human activities involving strong soil disturbance have significantly affected plant development. Therefore, currently it is a priority to avoid the deterioration of soil ecosystems to remediate the damages that have already occurred. In the case of soil microbiology area, there are many solutions that can be designed and applied with beneficial microorganisms, including both fungi and bacteria, that interact mutualistically with plants or crops. At the same time, a deep understanding of these interactions remains challenging due to their complexity. In this review, biotechnological developments with agricultural or forestry importance are analysed. These include plant growth promoter bacteria, the Azolla-Anabaena symbiotic system, arbuscular mycorrhizal fungi and ectomycorrhizal fungi, as well as their relevance in the production of agricultural and forestry biofertilizers.