Biology subjects

Porcar, M.

Publications and source records attributed to Porcar, M..

5 recordsLinked to original sources

bioRxiv2018

Microbial communities of the Mediterranean rocky coast: ecology and biotechnological potential

Microbial communities from harsh environments hold great promise as sources of biotechnologically-relevant strains. In the present work, we have deeply characterized the microorganisms from three different rocky locations of the Mediterranean coast, an environment characterised by being subjected to harsh conditions such as high levels of irradiation and large temperature and salinity fluctuations. Through culture-dependent and culture-independent techniques, we have retrieved a complete view of the ecology and functional aspects of these communities and assessed the biotechnological potential of the cultivable microorganisms. A culture-independent approach through high-throughput 16S rRNA amplicon sequencing revealed that all three locations display very similar microbial communities, suggesting that there is a stable community associated to the sampled region, with Stanieria cyanosphaera, Rubrobacter sp. and the families Flammeovirgaceae, Phyllobacteriaceae, Rhodobacteraceae and Trueperaceae being the most abundant taxa. Furthermore, shotgun metagenomic sequencing results were in concordance with the high-thoughput 16S rRNA, and allowed a description of the eukaryotic and archaeal members of the community, which were abundant in Ascomycota and halotolerant archaea, respectively. The culture-dependent approach yielded a collection of 100 isolates (mainly pigmented), out of which 12 displayed high antioxidant activities, as proved with two in vitro (hydrogen peroxide and DPPH) and an in vivo (model organism C. elegans) assays.

microbiology↗

bioRxiv2018

Bioprospecting the solar panel microbiome: high-throughput screening for antioxidant bacteria in a Caenorhabditis elegans model

Microbial communities that are exposed to sunlight typically share a series of adaptations to deal with the radiation they are exposed to, including efficient DNA repair systems, pigment production and protection against oxidative stress, which makes these environments good candidates for the search of novel antioxidant microorganisms. In this research project, we isolated potential antioxidant pigmented bacteria from a dry and highly-irradiated extreme environment: solar panels. High-throughput in vivo assays using Caenorhabiditis elegans as an experimental model demonstrated the high antioxidant and ultraviolet-protection properties of these bacterial isolates that proved to be rich in carotenoids. Our results suggest that solar panels harbor a microbial community that includes strains with potential applications as antioxidants.

microbiology↗

bioRxiv2018

Liquid co-substrates repower sewage microbiomes

A range of parameters are known to shape the methanogenic communities of biogas-producing digesters and to strongly influence the amount of biogas produced. In this work, liquid and solid fractions of grass biomass were used separately for semicontinuous batch methanation using sewage sludge as seed sludge. During 6 months of incubation, the amount of input COD was increased gradually, and the underlying methanogenic microbiome was assessed by means of microscopy-based automated cell counting and full-length 16S rRNA high-throughput sequencing. In this sense, we prove for the first time the suitability of the ONTMinION platform as a monitoring tool for anaerobic digestion systems. According to our results, solid-fed batches were highly unstable at higher COD input concentrations, and kept Methanosaeta spp. typically associated to sewage sludge-as the majoritary methanogenic archaea. In contrast, liquid-fed batches developed a more stable microbiome, proved enriched in Methanosarcina spp, and resulted in higher methanogenic yield. This work demonstrates the high repowering potential of microbiomes from sewage sludge digesters, and highlight the effectiveness of liquefied substrates for increasing biogas productivity in anaerobic digestions.

microbiology↗

bioRxiv2018

Thermoelectric Heat Exchange and Growth Regulation in a Continuous Yeast Culture

We have designed a thermoelectric heat exchanger (TEHE) for microbial fermentations, able to control the temperature of a microbial continuous culture, and produce electric power. The system proved able to stably maintain both the temperature and the optical density of the culture during the exponential, highly productive phase.

microbiology↗

bioRxiv2017

Warm and wet: robust lipase-producing bacteria from the indoor environment

Lipases are key biocatalysts with important biotechnological applications. With the aim of isolating robust lipolytic microbial strains, we have analyzed the bacterial communities inhabiting two domestic extreme environments: a thermophilic sauna and a dishwasher filter. Scanning electron microscopy revealed biofilm-forming and scattered microorganisms in the sauna and dishwasher sample, respectively. A culture-independent approach based on 16S rRNA analysis indicated a high abundance of Proteobacteria in the sauna sample; and, a large amount of Proteobacteria, Firmicutes, Cyanobacteria and Actinobacteria in the dishwasher filter. With a culture-dependent approach, we isolated 48 bacterial strains, screened their lipolytic activities on media with tributyrin as the main carbon source, and finally selected five isolates for further characterization. These strains, all of them identified as members of the genus Bacillus, displayed optimum lipolytic peaks at pH 6.5 and with 1-2% NaCl, and the activity proved very robust at a wide range of pH (up to 11.5) and added NaCl concentrations (up to 4%). The thermal, pH and salt robustness of the selected isolates is a valuable attribute for these strains, which are promising as highly tolerant biodetergents. To our knowledge, this is the first report regarding the isolation from an indoor environment of Bacillus strains with a high potential for industry.

microbiology↗