This review provides insights into cellulolytic bacteria present in global forest and agricultural soils over a period of 11 years. It delves into the study of soil-dwelling cellulolytic bacteria and the enzymes they produce, cellulases, which are crucial in both soil formation and the carbon cycle. Forests and agricultural activities are significant contributors to the production of lignocellulosic biomass. Forest ecosystems, which are key carbon sinks, contain 20–30% cellulose in their leaf litter. Concurrently, the agricultural sector generates approximately 998 million tons of lignocellulosic waste annually. Predominant genera include Bacillus, Pseudomonas, Stenotrophomonas, and Streptomyces in forests and Bacillus, Streptomyces, Pseudomonas, and Arthrobacter in agricultural soils. Selection of cellulolytic bacteria is based on their hydrolysis ability, using artificial cellulose media and dyes like Congo red or iodine for detection. Some studies also measure cellulolytic activity in vitro. Notably, bacterial cellulose hydrolysis capability may not align with their cellulolytic enzyme production. Enzymes such as GH1, GH3, GH5, GH6, GH8, GH9, GH10, GH12, GH26, GH44, GH45, GH48, GH51, GH74, GH124, and GH148 are crucial, particularly GH48 for crystalline cellulose degradation. Conversely, bacteria with GH5 and GH9 often fail to degrade crystalline cellulose. Accurate identification of cellulolytic bacteria necessitates comprehensive genomic analysis, supplemented by additional proteomic and transcriptomic techniques. Cellulases, known for degrading cellulose, are also significant in healthcare, food, textiles, bio-washing, bleaching, paper production, ink removal, and biotechnology, emphasizing the importance of discovering novel cellulolytic strains in soil.

Arid and semi-arid soils display low productivity due to abiotic stress associated with drought and salinity. Halobacteria can increase the yield of crops grown under these types of stress. These bacteria thrive across a wide salinity range (1–25% NaCl) and also in the absence of NaCl and have direct and indirect mechanisms that promote plant growth. This review summarizes studies conducted over the past five years that have assessed the effect of halobacteria on plants and soil fertility. The criteria used in the selection of halobacteria were also reviewed. Few studies have assessed the impact of halobacteria on soil fertility. The selection of halobacteria has been based on a qualitative criterion considering the morphology of colonies grown in media enriched with salts, mainly Na⁺. Not all bacteria growing in salt-enriched media are capable of capturing Na⁺ ions. Therefore, a quantitative criterion should be applied for the selection of halobacteria, which could be their ability to capture Na⁺ ions in vitro. This, together with the assessment of the effect of halobacteria on soil fertility, may largely contribute to the recovery of saline soils.

Enzymes are proteins that catalyze chemical reactions in living systems, transforming specific substrates into the products needed in biological cycles and for many edaphic processes. Soil enzymatic activities have been proposed as soil quality indicators, due to their relation with soil biology. Although the long-term effects of organic and mineral fertilization on physical and chemical soil properties have been previously studied, little is known about their effects on microbial community structure, microbial biomass carbon, microbial activity and enzymatic activity. Some studies report that organic and mineral fertilizers can affect, be it positively or negatively, microbial biomass size as well as soil microbial activity. This work examines the effect of fertilization on the enzymatic activity of soil hydrolases.