Microalgal symbiosis in biotechnology

This review provides an analysis of recent published work on interactions between microorganisms, especially the ones involving mainly nutrient exchanges and at least with one microalga species. Examples of microbial partners are given, with a remark to the potential application of cultures of an autotroph and a heterotroph, which grow simultaneously, taking advantage of the complementary metabolisms. These are particularly interesting, either due to economic or sustainable aspects, and some applications have already reached the commercial stage of development. The added advantages of these symbiotic cultures are biomass, lipid, and other products productivity enhancement a better utilization of resources and the reduction or even elimination of process residues (including carbon dioxide and other greenhouse gases) to conduct an increasingly greener biotechnology. Among the several symbiotic partners referred, the microalgae and yeast cultures are the most used. The interaction between these two microorganisms shows how to enhance the lipid production for biodiesel purposes compared with separated (stand-alone) cultures

Desalination in nuclear plants: a bibliometric study of research activity in scientific literature indexed by SCOPUS base

With the scarcity of fresh water, desalination is an important instrument to be considered for the production of non-salinized water through waste heat in the dual use of nuclear reactors. The gap that this study seeks to fill is related to the use of bibliometric method, based on information structure, about the scientific studies indexed on the evolution of the topic desalination in nuclear power plants. The objective of this work is to map the themes in the scientific literature between 1966 and the first semester of 2017. Data were collected from the research activities indexed by the SCOPUS database and analyzed with the support of bibliometric software VOSviewer. Among others, the results of the research led to the following conclusions: (1) the articles published in indexed journals represent the largest percentage of the type of instrument used for scientific dissemination, representing 64% of the documents; (2) it is estimated that between the years 2016 and 2025 the indexed research activities involving nuclear desalination continued to grow sharply

Energetic valorization of a heterotrophic microalga residue from biodiesel production through anaerobic digestion

Trabalho apresentado em WASTES: Solutions, Treatments and Opportunities, 5th International Conference, September 4th - 6th, Almada/Caparica, Portugal.The production of biodiesel from the oil fraction of the heterotrophically grown microalga Chlorella protothecoides generated two waste streams: defatted microalga residues and crude glycerol. These wastes were anaerobically digested separately and in admixture to quantify their energy potential. The defatted microalga residues (from the oil extraction process) were shown to be a suitable substrate for anaerobic digestion since they provided a methane yield of 498.4 mL CH4/g volatile solids (VS). On the other hand, because glycerol acted as an inhibitory agent for methanogenesis, anaerobic co-digestion of defatted microalga residues and crude glycerol resulted in the diversification of the produced energy carrier. By using glycerol at a ratio of 1.24 g glycerol/g volatile solids of inoculum in admixture with microalga residues, hydrogen was obtained instead of methane. The resulting yield was 39.9 mL H2/g VS of microalga residues. Based on these results, both effluents can be valorized through simple and sustainable methods in order to recover their energy potential in the form of methane or hydrogen.info:eu-repo/semantics/publishedVersio

Longevity and Parasitism Capacity of Psyttalia concolor (Hymenoptera: Braconidae) Fed on Sugar Solutions and Insect Honeydew

Sugars are important food sources required by adult parasitoid species to enhance their survival, fecundity and fitness. The beneficial capacity of Psyttalia concolor Szépligeti, as a biological control agent of different fruit fly pest species, is expected to increase when different sugar food sources are supplied. The objective of this study was to test the effect of seven sugars (glucose, fructose, sucrose, trehalose, melibiose, melezitose and sorbitol) on the longevity and parasitism capacity of P. concolor. Moreover, we evaluated the effect of two types of honeydew excreted by hemipteran pests present in olive trees, Saissetia oleae Olivier (Coccidae) and Euphyllura olivina (Costa) (Psyllidae) on the longevity of the parasitoid. Our results show a positive effect of carbohydrate (single sugars and honeydew) consumption on parasitoid survival. Female longevity increased when fed on sorbitol and melibiose, while males benefited from feeding on glucose and fructose, suggesting that hexose-nectars would benefit males. Sucrose increased the percentage of non-emerged hosts and parasitism rate while melezitose significantly decreased these percentages, compared to the other sugars offered. P. concolor benefited more from feeding on honeydew than on sugars, and this food item can represent an important source of energy for the parasitoid. This result indicates the importance of specific nutrients for promoting the action of P. concolor against pestsinfo:eu-repo/semantics/publishedVersio

Impact of brewery wastewater inhibitors in pure and mixed cultures of the yeast Rhodosporidium toruloides NCYC 921 and the microalga Tetradesmus obliquus ACOI 204/07

ABSTRACT: Brewery wastewater (BWW) is an appealing low-cost substrate for the production of single cell oils by oleaginous microorganisms. However, it may contain inhibitor compounds that may affect the microbial metabolism. This work investigated, for the first time, the presence of potential inhibitor compounds in primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) for the pure and mixed cultivation of the yeast Rhodosporidium toruloides NCYC 921 and the microalga Tetradesmus obliquus ACOI 204/07. Three organic acids (OrgAc) were identified in the brewery effluents (acetic, propionic and butyric acids). Yeast and microalga pure and mixed cultivations were performed in PBWW and SBWW in order to understand the behaviour of the microorganisms, individually and together. Flow cytometry (FC) was used to monitor each microbial population during the mixed cultivations, and to study the yeast and microalga cell viability throughout all cultivations. The yeast cells in pure cultures grown in both effluents were severely affected by the OrgAc presence confirmed by the cell stress results obtained by FC. However, in the mixed cultures, the yeast cells were able to develop, and the levels of stress conditions were considerably lower. Only in microalga pure and mixed cultures efficient OrgAc removal was observed.info:eu-repo/semantics/publishedVersio

Patrones de diversidad de Araneae en un gradiente de prácticas de cultivo en olivares: vinculados entre patrones del paisaje, prácticas de gestión e interacciones entre especies

Trabalho apresentado em XIX Jornadas del Grupo Ibérico de Aracnología, 4-6 outubro 2019, Priego, Espanha.N/

The Use of Oleaginous Yeasts and Microalgae Grown in Brewery Wastewater for Lipid Production and Nutrient Removal: A Review

ABSTRACT: Brewery wastewater has been proposed as an attractive low-cost substrate for microbial lipid production for oleaginous yeast and microalga with promising results. For each liter of beer produced, from 3 to 10 L of wastewater are generated which can be used as culture medium for autotrophic or heterotrophic metabolism. This strategy allows reducing the culture medium cost, as well as obtaining high lipid contents and other high value compounds which can make the process profitable. Additionally, the use of industrial effluents/wastes as substrates for microbial growth can be a strategy to treat them based on the circular economy rules. This review presents the different brewery wastewater treatment strategies using oleaginous yeast and microalga pure and mixed cultures for the concomitant wastewater treatment and lipids/carotenoids production so far reported, highlighting the benefits/disadvantages of such strategies and comparing their performance in terms of wastewater treatment, lipids and carotenoids production between pure and mixed cultures performance.info:eu-repo/semantics/publishedVersio

Concomitant wastewater treatment with lipid and carotenoid production by the oleaginous yeast Rhodosporidium toruloides grown on brewery effluent enriched with sugarcane molasses and urea

ABSTRACT: In this study, secondary brewery wastewater (SBWW) supplemented with sugarcane molasses (SCM) was used for SBWW treatment with concomitant lipid and carotenoid production by the yeast Rhodosporidium toruloides NCYC 921. In order to improve the biomass production, ammonium sulfate, yeast extract and urea were tested as nitrogen sources. Urea was chosen as the best low-cost nitrogen source. A fed-batch cultivation was carried out with SBWW supplemented with 10 g L−1 of sugarcane molasses as carbon source, and 2 g L−1 of urea as nitrogen source. A maximum biomass concentration of 42.5 g L−1 was obtained at t=126.5 h and the maximum biomass productivity was 0.55 g L−1 h−1 at t=48.25 h. The maximum lipid content was 29.9 % w/w (DCW) at t=94 h of cultivation and the maximum carotenoid content was 0.23 mg g−1 at 120 h of cultivation. Relatively to the SBWW treatment, after the batch phase, 45.8 % of total Kjeldahl nitrogen removal, 81.7 % of COD removal and 100 % of sugar consumption were observed. Flow cytometry analysis revealed that 27.27 % of the cells had injured membrane after the inoculation. This proportion was reduced to 10.37 % at the end of the cultivation, indicating that cells adapted to the growth conditions.info:eu-repo/semantics/publishedVersio

Effect of brewery effluent inhibitors on Rhodotorula toruloides NCYC 921 cells grown in pure and mixed cultures at pH 4 and 6

ABSTRACT: The presence of inhibitor compounds in the culture medium can cause severe effects on the microorganisms cells. Brewery wastewaters present organic acids (acetic, propionic and butyric acids) which can severely affect yeast cells metabolism, when grown in pure cultures, although in mixed cultures they are able to develop. To understand the physiological changes on Rhodotorula toruloides (formerly Rhodosporidium toruloides) cells when fermenting in the presence of the organic acids present in brewery wastewater, pure and mixed cultures with the microalga Tetradesmus obliquus were performed in a synthetic medium containing the same organic acids concentrations that are present in brewery wastewater at pH 4 and 6. It was concluded that, at pH 4, the organic acids effects in the yeast cells were much more toxic than at pH 6. Moreover, mixed cultures can be an advantage over heterotrophic pure cultures as the microalga is able to contribute for the consumption of potential inhibitors for the yeast.info:eu-repo/semantics/publishedVersio

Memória operatória em crianças surdas: estudo de alguns efeitos diferenciais

[Resumo] Este estudo procurou clarificar alguns problemas ou perturbações que as crianças surdas podem apresentar ao nível do funcionamento de alguns dos componentes da memória operatória (Baddeley e Hitch, 1974), bem como da atenção. Para avaliação da memória das crianças foram criadas provas informatizadas de memória para palavras, para números e para figuras. Para além disso foram também desenvolvidas duas provas de atenção: uma de atenção concentrada e outra de atenção distribuída. Os resultados serao analisados tendo em conta o grau de surdez das crianças e da escolaridade que possuem no momento de realização das provas