Bioaerosols are relevant for public health and may play an important role in the climate system, but their atmospheric abundance, properties, and sources are not well understood. Here we show that ...the concentration of airborne biological particles in a North American forest ecosystem increases significantly during rain and that bioparticles are closely correlated with atmospheric ice nuclei (IN). The greatest increase of bioparticles and IN occurred in the size range of 2–6 μm, which is characteristic for bacterial aggregates and fungal spores. By DNA analysis we found high diversities of airborne bacteria and fungi, including groups containing human and plant pathogens (mildew, smut and rust fungi, molds, Enterobacteriaceae, Pseudomonadaceae). In addition to detecting known bacterial and fungal IN (Pseudomonas sp., Fusarium sporotrichioides), we discovered two species of IN-active fungi that were not previously known as biological ice nucleators (Isaria farinosa and Acremonium implicatum). Our findings suggest that atmospheric bioaerosols, IN, and rainfall are more tightly coupled than previously assumed.
Archaea are widespread and abundant in many terrestrial and aquatic environments, and are thus outside extreme environments, accounting for up to ~10% of the prokaryotes. Compared to bacteria and ...other microorganisms, however, very little is known about the abundance, diversity, and dispersal of archaea in the atmosphere. By means of DNA analysis and Sanger sequencing targeting the 16S rRNA (435 sequences) and amoA genes in samples of air particulate matter collected over 1 year at a continental sampling site in Germany, we obtained first insights into the seasonal dynamics of airborne archaea. The detected archaea were identified as Thaumarchaeota or Euryarchaeota, with soil Thaumarchaeota (group I.1b) being present in all samples. The normalized species richness of Thaumarchaeota correlated positively with relative humidity and negatively with temperature. This together with an increase in bare agricultural soil surfaces may explain the diversity peaks observed in fall and winter. The detected Euryarchaeota were mainly predicted methanogens with a low relative frequency of occurrence. A slight increase in their frequency during spring may be linked to fertilization processes in the surrounding agricultural fields. Comparison with samples from the Cape Verde islands (72 sequences) and from other coastal and continental sites indicates that the proportions of Euryarchaeota are enhanced in coastal air, which is consistent with their suggested abundance in marine surface waters. We conclude that air transport may play an important role in the dispersal of archaea, including assumed ammonia-oxidizing Thaumarchaeota and methanogens.
This work evaluated the degradation of sugarcane vinasse with the production of biomass by Pleurotus sajor-caju CCB020, considering the combination of temperature and pH effects, using surface ...response methodology (RSM). A 22 complete central factorial composite experiment was used to analyze the results. The optimum temperature and pH values were respectively 27 °C and 5.6 for maximum decolorization yield and 20 °C and 6.8 for maximum biomass production. In parallel, scale-up experiments under conditions of 30 °C and initial pH 5.0 were evaluated in two different air-lift bioreactors of 7.0 L. Under these conditions, reductions of 53% and 58% in chemical oxygen demand (COD) and 71% and 58% in biological oxygen demand (BOD) were obtained respectively with the concentric tube type air-lift bioreactor with an increased degassing zone and without an increased degassing zone. Under these conditions, this study concluded that the systematic combination of P. sajor-caju and vinasse can be applied in the biodegradation process of refractory compounds contained in vinasse, concomitant to obtaining biomass and laccase and manganese peroxidase enzymes. Due to the good performance of the air-lift bioreactors, they can be used in scale studies in future industrial vinasse applications, besides it is possible to emphasize that different configurations in the bioreactor can affect the efficiency of the process.
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•Pleurotus sajor-caju exhibited high degradation potential of vinasse.•Air-lift bioreactors had a good performance and may be used in scale-up studies.•Different configurations of the bioreactor affect the efficiency of the process.•P. sajor-caju presented high capacity for the production of enzymes and biomass when cultivated in vinasse.
Xanthan gum (XG) is a biopolymer obtained in fermentation and used as a rheology control agent in aqueous systems and in stabilizing emulsions and suspensions. XG, together with other ...polysaccharides, can form soft, cohesive composite gels. The carbon source in the fermentative process is responsible for one-third of the production costs, and the search for less expensive and sustainable alternatives is ongoing. The use of agricultural residues such as the corncob is highly suggestive due to their abundance. This study aims to evaluate the use of derived hemicellulose fractions from the alkaline extraction of corncob as a carbon source in the production of XG in trials using four strains of Xanthomonas sp. (629, 1078, 254, and S6). The results indicate that strain 629 provides the higher yield (8.37 ± 5.75 g L−1) while using a fermentation medium containing a carbon source of saccharose (1.25%), hemicellulose fractions (3.75%), and salts. In this same medium, the strain 629 produces gum in 3% aqueous solution, showing the higher apparent viscosity (9298 ± 31 mPa s−1) at a shear rate of 10 s−1 at 25 °C. In conclusion, corncob is proven to be a promising sustainable alternative carbon source in the obtention of XG, improving the economic viability of the process within a biorefinery context. Saccharose must, however, also be included in the fermentation medium.
Xanthan gum (XG) is a biopolymer obtained in fermentation and used as a rheology control agent in aqueous systems and in stabilizing emulsions and suspensions. XG, together with other ...polysaccharides, can form soft, cohesive composite gels. The carbon source in the fermentative process is responsible for one-third of the production costs, and the search for less expensive and sustainable alternatives is ongoing. The use of agricultural residues such as the corncob is highly suggestive due to their abundance. This study aims to evaluate the use of derived hemicellulose fractions from the alkaline extraction of corncob as a carbon source in the production of XG in trials using four strains of Xanthomonas sp. (629, 1078, 254, and S6). The results indicate that strain 629 provides the higher yield (8.37 ± 5.75 g Lsup.−1 ) while using a fermentation medium containing a carbon source of saccharose (1.25%), hemicellulose fractions (3.75%), and salts. In this same medium, the strain 629 produces gum in 3% aqueous solution, showing the higher apparent viscosity (9298 ± 31 mPa ssup.−1 ) at a shear rate of 10 ssup.−1 at 25 °C. In conclusion, corncob is proven to be a promising sustainable alternative carbon source in the obtention of XG, improving the economic viability of the process within a biorefinery context. Saccharose must, however, also be included in the fermentation medium.
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•Conversion of agro-industrial lignocellulosic residues into value-added products.•Alkaline and autohydrolysis lignocellulose pre-treatments to obtain liquors.•Liquors used as carbon ...sources inducing xylanase production by Aspergillus sp.
Enzymes represent a growing market due to their industrial applications, whose use on a large scale is restricted by their high cost of production. This stimulates studies with other sources such as the use of agro-industrial lignocellulosic residues in the medium composition for its production. Thus, in this work, in natura sunflower stalks (Helianthus annuus L.) and its respective alkaline and autohydrolysis pre-treatment liquors were used as carbon sources inducing xylanase production by Aspergillus sp. fermentation. Results showed xylanasic activities of 2.97 and 4.91 U/mL, using alkaline and autohydrolysis liquors, respectively, while the in natura residue displayed the highest value (17.48 U/mL). On the other hand, the in natura sunflower stalk + liquors (alkaline and autohydrolysis, separately) blend significantly improved enzyme production, 6.34 and 11.98 U/mL, compared with the use of each liquor as the sole source inducing. Therefore, sunflower stalks and their liquors are potential inducing sources for the xylanase production, compared with the commercial purified xylan.
In recent years, the oil industry has developed increasingly by creating continuous innovation system, whether identifying barriers, evaluating new possibilities, integrating systems, adding value to ...research and development to overcome commonly encountered challenges. In this respect, the operations concerning the treatment of produced water stand out. In dynamic environments, these Foresights must be constantly updated. The present work sought to identify factors that provide directions to understand future scenarios for the treatment process of produced water from the oil industry. The methodology used was initially based on the Delphi method, which was applied to direct and concatenate opinions obtained through a consensus among experts in the field. Additionally, the SAPEVO-M tool was implemented to assist decision-making based on the identified scenarios, evaluating, in advance, the risks, uncertainties, and possibilities involved in the treatment of produced water. The results obtained allowed us to infer potential technological scenarios, especially sustainable processes, which will be promising and challenging for the oil industry in the medium and long term, a period necessary for the maturation of the potential technologies used. In addition, a critical assessment of existing risks in each technology to minimize future uncertainties was considered.
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