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.

Las rizobacterias promotoras del crecimiento vegetal (RPCV) son bioestimulantes que favorecen el crecimiento de las plantas. Se evaluó el efecto de la inoculación de RPCV para promover el crecimiento de plantas de chile (Capsicum annuum L.) y lechuga (Lactuca sativa L.). Se utilizó un diseño experimental de 5 tratamientos y 4 repeticiones para cada cultivo. Las especies bacterianas fueron Achromobacter xylosoxidans (C56), Arthobacter pokkalii (JLB4), Bacillus pumilus (AV5) y su combinación como consorcio. Las variables evaluadas fueron: altura, diámetro del tallo, índice relativo de clorofila (SPAD) y peso fresco de parte aérea. En estos experimentos se observaron diferencias significativas de la bacteria C56 para estimular un 11% la altura de plantas de lechuga, comparada con los demás tratamientos. El consorcio de bacterias estimula un 7.8% el índice relativo de clorofila en lechuga, además de mostrar una tendencia positiva del consorcio para estimular el peso fresco aéreo de ambos cultivos. El uso de RPCV en consorcio es una alternativa que se debe seguir estudiando para minimizar el uso de productos químicos, potenciar la agricultura y mitigar el cambio climático.

Pellets are ultrastructural configurations of filamentous fungal biomass that form during growth in submerged culture. This growth pattern offers advantages for controlling and stabilizing bioprocesses through biomass immobilization, reduced medium viscosity, and facilitated compound extraction. These benefits are particularly valuable for bioremediation, synergistic applications with biomaterials, and industrial metabolite production. However, fungal pellets also present challenges, such as limited oxygen diffusion to the pellet core, inconsistent pellet homogeneity, and decreased productivity. Factors such as electrostatic interactions, hydrophobicity, and culture conditions influence pellet formation. Currently, optimization efforts for pellet production focus on evaluating parameters, such as: pH range, agitation rate, pellet formation time, carbon source, additive agents, trace metals, and inoculum concentration, among others. Fungal pellets are increasingly recognized as promising platforms in emerging environmental biotechnology due to their versatility in pollutant removal and sustainable processing. Unlike previous reviews, this work provides an integrated and up-to-date perspective that combines the fundamentals of pellet formation with recent advances in their environmental and industrial applications, highlighting strategies for optimization and scalability. This review focuses on analyzing the most relevant aspects of fungal pellets, including their formation, optimization, and biotechnological applications. Given the growing importance of fungi in contemporary biotechnology, a state-of-the-art review of fungal pellets is warranted. This includes presenting an updated overview of processes for generating fungal biomass with enhanced handling, based on the use of fungal granules, an essential component for the implementation of efficient biotechnological processes using model fungal pellets with relevant industrial applications.

El pak choi es una hortaliza de alto valor nutricional y palatabilidad, lo que ha promovido el aumento de su cultivo y consumo fuera de Asia, su región originaria. En este trabajo se evaluó el efecto de la inoculación de tres cepas de rizobacterias promotoras de crecimiento vegetal (RPCV) Arthrobacter pokkalii JLB4, Pseudomonas tolaasii P61 y Pseudomonas tolaasii A46 en plantas de pak choi en condiciones controladas en un macro túnel, en 2021. Se utilizaron como testigo plántulas de pak choi sin inoculación y se realizaron dos inoculaciones, la primera inmediatamente después del trasplante de las plántulas a bolsas con 5 kg de suelo y la segunda un mes después. Las plantas se fertilizaron simultáneamente con la inoculación con NPK en proporción 164-53-187. Los resultados obtenidos mostraron que la cepa Pseudomonas tolaasii P61 fue la que tuvo el mayor efecto en el peso seco (23.04 ±0.057 g planta-1), así como en el contenido de P (0.1704 ±0.001 g planta-1) y S (0.1847 ±0.004 g planta-1) comparados con el control, con incrementos de 11.5%, 10.8% y 12.3%, respectivamente. La cepa Arthrobacter pokkalii JLB4 provocó mayor crecimiento de la raíz, el volumen radical (75 ±5 ml) 49% fue superior al testigo. Sin embargo, no tuvo efecto en el peso seco de parte aérea. Los resultados sugieren que el uso combinado de fertilizante y RPCV conduce a mayor acumulación de biomasa y de nutrientes como el P, K y S que la sola aplicación de fertilizante.