Las microalgas son organismos fotoautótrofos con un rápido crecimiento y la habilidad de adaptarse a diversos ambientes. Convierten el dióxido de carbono en biomasa y debido a esto, se considera que tienen gran potencial biotecnológico. La biomasa algal puede usarse en la industria alimenticia y de compuestos bioactivos, en la producción de biocombustibles, en la bioremediación y biofertilización. Como biofertilizantes, las microalgas clorofitas y cianofitas, producen polisacáridos (mucílago) que pueden evitar la erosión, mejorar la estructura y el contenido de material orgánica de los suelos, y aumentar la concentración de iones en los cultivos. Reduciendo de esta forma la necesidad de fertilizantes químicos convencionales. El uso de estas microalgas como biofertilizantes se denomina algalización. Durante este proceso se usan principalmente clorofitas por su alta tasa de crecimiento, la facilidad de su cultivo a gran escala, y su adaptación a las condiciones del suelo. El género Chlorella es de gran interés porque diversos estudios han mostrado que puede ayudar en la fijación del nitrógeno, mejorar las propiedades físicas y químicas del suelo, y producir sustancias que promueven el desarrollo de la planta y el control de infecciones. Por esta razón, las microalgas del género Chlorella representan una alternativa viable para la biofertilización, generando beneficios no solo para la producción agrícola sino también para el medio ambiente.

Piscine orthoreovirus (PRV) is a pathogen that causes heart and skeletal muscle inflammation in Salmo salar and has also been linked to circulatory disorders in other farmed salmonids, such as Oncorhynchus kisutch and Oncorhynchus mykiss. The virus has a segmented, double-stranded RNA genome, which makes it possible to undergo genetic reassortment and increase its genomic diversity through point mutations. In this study, genetic reassortment in PRV was assessed using the full genome sequences available in public databases. This study used full genome sequences that were concatenated and genome-wide reassortment events, and phylogenetic analyses were performed using the recombination/reassortment detection program version 5 (RDP5 V 5.5) software. Additionally, each segment was aligned codon by codon, and overall mean distance and selection was tested using the Molecular Evolutionary Genetics Analysis X software, version 10.2 (MEGA X version 10.2). The results showed that there were 17 significant reassortment events in 12 reassortant sequences, involving genome exchange between low and highly virulent genotypes. PRV sequences from different salmonid host species did not appear to limit the reassortment. This study found that PRV frequently undergoes reassortment events to increase the diversity of its segmented genome, leading to antigenic variation and increased virulence. This study also noted that to date, no reassortment events have been described between PRV-1 and PRV-3 genotypes. However, the number of complete genomic sequences within each genotype is uneven. This is important because PRV-3 induces cross-protection against PRV-1, making it a potential vaccine candidate.

Mathematical models provide information about population dynamics under different conditions. In the study, four models were evaluated and employed to describe the growth kinetics of Nostoc ellipsosporum with different light wavelengths: Baranyi-Roberts, Modified Gompertz, Modified Logistic, and Richards. N. ellipsosporum was grown in BG-11 liquid medium for 9 days, using 12 hours of photoperiod and the following treatments: white light (400-800 nm), red light (650-800 nm), yellow light (550-580 nm) and blue light (460-480 nm). Each experiment was performed in triplicate. The optical density (OD) was measured on days 1, 3, 5, 7 and 9, using a spectrophotometer at 650 nm. The maximum cell growth was obtained under white light (OD650 : 0.090 ± 0.008), followed by the yellow light (OD650 :0.057 ± 0.004). Conversely, blue light showed a marked inhibitory effect on the growth of N. ellipsosporum (OD650 : 0.009 ± 0.001). The results revealed that the Baranyi-Roberts model had a better fit with the experimental data from N. ellipsosporum growth in all four treatments. The findings from this modeling study could be used in several biotechnological applications that require the productionof N. ellipsosporum and its bioproducts.

Nostoc is a genus of filamentous cyanobacteria with biotechnological applications in human nutrition, biomedicine, biofertilization and commercial production of biofuels. However, the low growth rate in liquid medium due to its periphytic nature and its tendency to form biofilms, limits its large-scale production. Therefore, the aim of this study was to evaluate the biomass production of Nostoc muscorum in a modified hydroponic system. Cultures of N. muscorum were made by triplicate, in a hydroponic system under semicontrolled conditions of temperature (29 ± 13 °C), light intensity (32 ± 54 μmol/m2/s) and photoperiod (12 hours), for a total of 23 days inside a greenhouse. Temperature, pH, conductivity and dry biomass production were monitored on alternating days. The results showed that the maximum dry biomass production was 0.2276 ± 0.0114 g/m2/day, and the average productivity was 0.4149 ± 0.0207 g/m2/day. The maximum biomass production of N. muscorum was achieved on day thirteen with 0.3185 ± 0.0159 g/m2/day. The correlation statistical analysis of environmental variables did not show significant differences; thus, temperature, pH and electrical conductivity did not affect the biomass production of N. muscorum. Consequently, the algal growth was influenced by the species physiology only. The support used in the hydroponic system allowed the adhesion and development of the algae mucilaginous layer without requiring drying periods as in conventional crops. The hydroponic system provided a continuous flow of nutrients that could prevent the attack of opportunistic bacteria and fungi, generating a high growth rate of N. muscorum. The hydroponic system represents a viable alternative for the production of N. muscorum biomass under greenhouse conditions at large scale.

Chlorophyta and Cyanophyta are photosynthetic organisms characterized by their biochemical plasticity, which has allowed them to develop in different environments and have a faster growth rate than plants. Depending on the species and environmental conditions, these organisms can produce nitrogenous enzymes, for atmospheric nitrogen fixation; phosphatases, that solubilize phosphorus; phytohormones, that promote plant growth; and hygroscopic polysaccharides, that prevent erosion and improve soil characteristics. In this sense, the aim of this review was to analyze the available information on the use of Chlorophyta and Cyanophyta as biofertilizers and their potential application in organic food production. Multiple studies and researches were found demonstrating the advantages of these microorganisms when being used to improve plants productivity, and also at the same time, leading to sustainable agriculture that is respectful to the environment. However, their high production cost has become a limiting factor for their commercialization.