Bacteria produce antimicrobial compounds to compete for nutrients and space in a particular habitat. Antagonistic interactions can be evaluated by several methodologies including the double-layer agar and simultaneous inhibition assays. Among the well-known inhibitory substances produced by bacteria are the broad-spectrum antibiotics, organic acids, siderophores, antifungal, and bacteriocins. The most studied bacterial genera able to produce these inhibitory substances are Enterococcus, Lactococcus, Streptomyces, Bacillus, Pseudomonas, Klebsiella, Escherichia, and Burkholderia. Some beneficial bacteria can promote plant growth and degrade toxic compounds in the environment representing an attractive solution to diverse issues in agriculture and soil pollution, particularly in fields with damaged soils where pesticides and fertilizers have been indiscriminately used. Beneficial bacteria may increase plant health by inhibiting pathogenic microorganisms; some examples include Gluconacetobacter diazotrophicus, Azospirullum brasilense, Pseudomonas fluorescens, Pseudomonas protegens, and Burkholderia tropica. However, most studies showing the antagonistic potential of these bacteria have been performed in vitro, and just a few of them have been evaluated in association with plants. Several inhibitory substances involved in pathogen antagonism have not been elucidated yet; in fact, we know only 1 % of the bacterial diversity in a natural environment leading us to assume that many other inhibitory substances remain unexplored. In this review, we will describe the characteristics of some antimicrobial compounds produced by beneficial bacteria, the principal methodologies performed to evaluate their production, modes of action, and their importance for biotechnological purposes.

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Due to the constant growth of the human population and anthropological activity, it has become necessary to use sustainable and affordable technologies that satisfy the current and future demand for agricultural products. Since the nutrients available to plants in the soil are limited and the need to increase the yields of the crops is desirable, the use of chemical (inorganic or NPK) fertilizers has been widespread over the last decades, causing a nutrient shortage due to their misuse and exploitation, and because of the uncontrolled use of these products, there has been a latent environmental and health problem globally. For this reason, green biotechnology based on the use of microalgae biomass is proposed as a sustainable alternative for development and use as soil improvers for crop cultivation and phytoremediation. This review explores the long-term risks of using chemical fertilizers for both human health (cancer and hypoxia) and the environment (eutrophication and erosion), as well as the potential of microalgae biomass to substitute current fertilizer using different treatments on the biomass and their application methods for the implementation on the soil; additionally, the biomass can be a source of carbon mitigation and wastewater treatment in agro-industrial processes.

Introduction: Ganoderma lucidum is one of the most worldwide known medicinal mushrooms. However, this species of mexican mushroom has notable differences compared to its similar one since it has not been studied enough so it is important to determine its characteristics once it has been cultivated and its extracts have obtained in a standardized form.Method: The polysaccharides of the extracts of Ganoderma lucidum strain CP-145 were measured by the quantum magnetic resonance analyzer MARSIII of Bruce Copen (MARSIII), a proposed technique to estimate values of compounds in the agricultural area, these results were compared with two standardized techniques: Fehling method of sugar reducers and Gas Chromatography - Mass spectrometry (GC-MS), the extracts to be measured were obtained from the traditional culture of basidiocarps (control) and extract of basidiocarps added with acetylsalicylic acid (ASA).Results: The results for the MARSIII quantum magnetic analyzer were 4.967 ± 1.016 and 8.110 ± 1.416% in control extract and extract added respectively, by the Fehling´s method 8.784 ± 2.019% and 41.326 ± 1.430% in control extract and extract added respectively, for CG- MS 7.050 ± 1.527 and 18.456 ± 2.937% in control extract and extract added respectively.                      Discussion and Conclusion: Significant differences were found on the Fehling´s techniques and on the GC-MS for both extracts, but not in the MARSIII analyzer detection, which indicates that it is not an adequate method to detect variations in the concentrations of polysaccharides in this type of extracts. 

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