Publications by authors named "Germán Tortosa"

8 Publications

  • Page 1 of 1

Involvement of the metabolically active bacteria in the organic matter degradation during olive mill waste composting.

Sci Total Environ 2021 Oct 25;789:147975. Epub 2021 May 25.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ), Agencia Estatal CSIC, c/ Profesor Albareda, 1, 18008 Granada, Spain.

RNA-based high-throughput sequencing is a valuable tool in the discernment of the implication of metabolically active bacteria during composting. In this study, "alperujo" composting was used as microbial model for the elucidation of structure-function relationships with physicochemical transformation of the organic matter. DNA and RNA, subsequently retrotranscribed into cDNA, were isolated at the mesophilic, thermophilic and maturation phases. 16S rRNA gene was amplified by quantitative PCR (qPCR) and Illumina MiSeq platform to assess bacterial abundance and diversity, respectively. The results showed that the abundance of active bacteria assessed by qPCR was maximum at thermophilic phase, which confirm it as the most active stage of the process. Concerning diversity, Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the main phyla presented in composts. Concomitantly, three different behaviours were observed for bacterial dynamics: some genera decreased during the whole process meanwhile others proliferated only at thermophilic or maturation phase. Statistical correlation between physicochemical transformations of the organic matter and bacterial diversity revealed bacterial specialisation. This result indicated that specific groups of bacteria were only involved in the organic matter degradation during bio-oxidative phase or humification at maturation. Metabolic functions predictions confirmed that active bacteria were mainly involved in carbon (C) and nitrogen (N) cycles transformations, and pathogen reduction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.147975DOI Listing
October 2021

The Hemoglobin Bjgb From Controls NO Homeostasis in Soybean Nodules to Protect Symbiotic Nitrogen Fixation.

Front Microbiol 2019 10;10:2915. Epub 2020 Jan 10.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.

Legume-rhizobia symbiotic associations have beneficial effects on food security and nutrition, health and climate change. Hypoxia induced by flooding produces nitric oxide (NO) in nodules from soybean plants cultivated in nitrate-containing soils. As NO is a strong inhibitor of nitrogenase expression and activity, this negatively impacts symbiotic nitrogen fixation in soybean and limits crop production. In , denitrification is the main process involved in NO formation by soybean flooded nodules. In addition to denitrification, nitrate assimilation is another source of NO in free-living cells and a single domain hemoglobin (Bjgb) has been shown to have a role in NO detoxification during nitrate-dependent growth. However, the involvement of Bjgb in protecting nitrogenase against NO in soybean nodules remains unclear. In this work, we have investigated the effect of inoculation of soybean plants with a mutant on biological nitrogen fixation. By analyzing the proportion of N in shoots derived from N-fixation using the N isotope dilution technique, we found that plants inoculated with the mutant strain had higher tolerance to flooding than those inoculated with the parental strain. Similarly, reduction of nitrogenase activity and expression by flooding was less pronounced in than in WT nodules. These beneficial effects are probably due to the reduction of NO accumulation in flooded nodules compared to the wild-type nodules. This decrease is caused by an induction of expression and activity of the denitrifying NO reductase enzyme in bacteroids. As deficiency promotes NO-tolerance, the negative effect of NO on nitrogenase is partially prevented and thus demonstrates that inoculation of soybean plants with the mutant confers protection of symbiotic nitrogen fixation during flooding.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2019.02915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6965051PMC
January 2020

Assessment of the diversity and abundance of the total and active fungal population and its correlation with humification during two-phase olive mill waste (''alperujo") composting.

Bioresour Technol 2020 Jan 15;295:122267. Epub 2019 Oct 15.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ), Agencia Estatal CSIC, c/Profesor Albareda, 1, 18008 Granada, Spain.

Metagenomic and transcriptomic techniques applied to composting could increase our understanding of the overall microbial ecology and could help us to optimise operational conditions which are directly related with economic interest. In this study, the fungal diversity and abundance of two-phase olive mill waste ("alperujo") composting was studied using Illumina MiSeq sequencing and quantitative PCR, respectively. The results showed an increase of the fungal diversity during the process, with Ascomycota being the predominant phylum. Penicillium was the main genera identified at the mesophilic and maturation phases, with Debaryomyces and Sarocladium at the thermophilic phase, respectively. The fungal abundance was increased during composting, which confirms their important role during thermophilic and maturation phases. Some Basidiomycota showed an increased during the process, which showed a positive correlation with the humification parameters. According to that, the genus Cystofilobasidium could be used as a potential fungal biomarker to assess alperujo compost maturation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biortech.2019.122267DOI Listing
January 2020

Spatio-Temporal Variations in the Abundance and Structure of Denitrifier Communities in Sediments Differing in Nitrate Content.

Curr Issues Mol Biol 2017 6;24:71-102. Epub 2017 Jul 6.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Granada, Spain.

Spatial and temporal variations related to hydric seasonality in abundance and diversity of denitrifier communities were examined in sediments taken from two sites differing in nitrate concentration along a stream Doñana National Park during a 3-year study. We found a positive relationship between the relative abundance of denitrifiers, determined as , , , and denitrification genes, and sediment nitrate content, with similar spatial and seasonal variations. However, we did not find association between denitrification activity and the community structure of denitrifiers. Because showed the strongest correlation with the content of nitrate in sediments, we used this gene as a molecular marker to construct eight genomic libraries. Analysis of these genomic libraries revealed that diversity of the -bearing communities was higher in the site with higher nitrate content. Regardless of nitrate concentration in the sediments, the Bradyrhizobiaceae and Rhodocyclaceae were the most abundant families. On the contrary, Rhizobiaceae was exclusively present in sediments with higher nitrate content. Results showed that differences in sediment nitrate concentration affect the composition and diversityof -bearing communities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.21775/cimb.024.071DOI Listing
September 2018

Evolution of bacterial diversity during two-phase olive mill waste ("alperujo") composting by 16S rRNA gene pyrosequencing.

Bioresour Technol 2017 Jan 29;224:101-111. Epub 2016 Nov 29.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ), Agencia Estatal CSIC, E-419, 18080-Granada, Spain.

Microorganisms are the main contributing factor responsible for organic matter degradation during composting. In this research, the 454-pyrosequencing of the 16S rRNA gene was used to elucidate evolution of bacterial diversity during mesophilic, thermophilic and maturation composting stages of the two-phase olive mill waste ("alperujo"), the main by-product of the Spanish olive oil industry. Two similar piles were performance composting AL with sheep manure as bulking agent. Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria were the main phyla found in genomic libraries from each composting phase. Shannon and Chao1 biodiversity indices showed a clear difference between the mesophilic/thermophilic and maturation phases, which was mainly due to detection of new genera. PCA analysis of the relative number of sequences confirmed maturation affected bacterial population structure, and Pearson correlation coefficients between physicochemical composting parameters and relative number of genera sequences suggest that Planomicrobium and Ohtaekwangia could be considered as biomarkers for AL composting maturation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biortech.2016.11.098DOI Listing
January 2017

Spatial distribution of N-cycling microbial communities showed complex patterns in constructed wetland sediments.

FEMS Microbiol Ecol 2013 Feb 24;83(2):340-51. Epub 2012 Sep 24.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Agencia CSIC, Granada, Spain.

Constructed wetlands are used for biological treatment of wastewater from agricultural lands carrying pollutants such as nitrates. Nitrogen removal in wetlands occurs from direct assimilation by plants and through microbial nitrification and denitrification. We investigated the spatial distribution of N-cycling microbial communities and genes involved in nitrification and denitrification in constructed wetland sediments receiving irrigation water. We used quantitative real-time PCR (qPCR) to characterize microbial communities. Geostatistical variance analysis was used to relate them with vegetation cover and biogeochemical sediment properties. The spatial distribution of the N-cycling microbial communities of sediments was heterogeneous and complex. Total communities of bacteria and crenarchaea showed different spatial distributions. Analysis of autocorrelation patterns through semivariance indicated a tendency towards a patchy distribution over scales around 10 m for genes involved in the nitrification and denitrification processes. In contrast, biogeochemical sediment properties showed diverse spatial distributions. While almost no patchiness was found for pH and moisture, patchiness at scales between 8 and 10 m was detected for carbon, nitrate and ammonia. Denitrification variables showed spatial autocorrelation at scales comparable to genes. However, denitrifying enzyme activity and potential N(2)O production showed a common spatial pattern, different from that of the N(2)O/(N(2)O + N(2)).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1574-6941.2012.01479.xDOI Listing
February 2013

Impact of fresh and composted solid olive husk and their water-soluble fractions on soil heavy metal fractionation; microbial biomass and plant uptake.

J Hazard Mater 2011 Feb 8;186(2-3):1283-9. Epub 2010 Dec 8.

Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafología y Biología Aplicada del Segura, CSIC, P.O. Box 164, 30100 Murcia, Spain.

The use of waste materials as organic amendments in soil remediation can affect metal solubility; this interaction will vary with the characteristics of the organic matter that is added to the soil. A pot experiment was carried out in a calcareous, metal-polluted soil, using Beta maritima L. as an indicator species for the treatment effects on metal solubility. The treatments were: fresh solid olive husk, a mature compost, their respective water extracts (as the most reactive and biodegradable fraction) and an unamended, control soil. The compost reduced metal availability and plant uptake, while fresh olive husk favoured Mn bioavailability and produced phytotoxicity. The water-soluble extract from fresh solid olive husk also provoked elevated Mn solubility in soil, but did not increase Mn uptake by plants. The application of water-soluble organic matter obtained from compost did not affect heavy metal solubility significantly. Therefore, composted olive husk seems to be the most-appropriate material for the development of bioremediation strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2010.12.004DOI Listing
February 2011

Evaluation of "alperujo" composting based on organic matter degradation, humification and compost quality.

Biodegradation 2009 Apr 24;20(2):257-70. Epub 2008 Sep 24.

Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Cientificas, Murcia, Spain.

The main by-product generated by the Spanish olive oil industry, a wet solid lignocellulosic material called "alperujo" (AL), was evaluated as a composting substrate by using different aeration strategies and bulking agents. The experiments showed that composting performance was mainly influenced by the type of bulking agent added, and by the number of mechanical turnings. The bulking agents tested in this study were cotton waste, grape stalk, a fresh cow bedding and olive leaf; the latter showed the worse performance. Forced ventilation alone was revealed to work inadequately in most of the experiments. The composting process involved a substantial degradation of the organic substrate with average losses of 48.4, 28.6, 53.7 and 57.0% for total organic matter, lignin, cellulose and hemicellulose, respectively. Both organic matter biodegradation and humification were greatly influenced by the lignocellulosic nature of the starting material, which led to low organic matter and nitrogen loss rates and a progressive increase in more humified substances, as revealed by the end-values of the humification indices. The resulting composts were of good quality in terms of nutrient content, stabilised and non-phytotoxic organic matter and low heavy metal content. This demonstrates that composting technology can be used as an alternative treatment method to turn AL into compost that can be used as organic amendments or fertilisers for agricultural systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10532-008-9218-yDOI Listing
April 2009
-->