Microalgae: The Basis of Mankind Sustainability

Microalgae were the basis of life into the planet, but only recently these microorganisms are exploited at a commercial scale. Thus, the production of pharmaceuticals, cosmetics, feed, and foods from microalgae is today a commercial reality increasing year by year. Additionally, microalgae have been proposed to be used to enhance the sustainability of existing industrial activities, as wastewater treatment and biofuel production. In this way, the utilization of microalgae at a large scale is considered a green revolution in the sustainability of mankind. This chapter is focused on reviewing the real contribution of microalgae to human activities. The last improvements of technologies and its uses, in addition to still existing bottlenecks for the massive exploitation of these microorganisms, are reviewed

Microalgae research worldwide

In this paper, worldwide research trends in the microalgae field are analyzed based on a bibliometric study. We have looked at the number of publications and their distribution, as well as the most relevant journals and keywords, to determine the evolution and latest tendencies in this field. The results confirm that this is a fast-growing area in terms of the number of publications. The most relevant journals on this subject are Bioresource Technology and Algal Research. Although the majority of papers come out of the USA, the most relevant institutions are actually located in China, France and Spain. The most frequently cited strains are Chlorella and Chlamydomonas. The main keywords that appear in over 1,000 articles are generally related to microalgae cultivation applications such as ‘biomass, biofuel, and lipids’ while others are related to the methodology; for instance, ‘bioreactor’. Of all the keywords, ‘biomass’ stands out, as it appears in almost 20% of publications. Bibliographic analysis confirms that Microalgae Biotechnology is a very active field, where scientific productivity has exponentially increased over recent years in tandem with industrial production. Therefore, expectations are high in this field for the near future

A new approach for detection and quantification of microalgae in industrial-scale microalgal cultures

In industrial-scale cultures, non-target microalgae compete with the desired species for nutrients and CO2, thus reducing the growth rate of the target species and the quality of the produced biomass. Microalgae identification is generally considered a complicated issue although, in the last few years, new molecular methods have helped to rectify this problem. Of the different techniques available, DNA barcoding has proven very useful in providing rapid, accurate and automatable species identification; in this work, it is used to assess the genomic identity of the microalga species Scenedesmus almeriensis, a common strain in industrial-scale cultures. Barcode markers rbcL and ITS1-5.8S-ITS2 were sequenced and the obtained genomic information was used to design a quantitative PCR assay to precisely quantify the S. almeriensis concentration in microalgal cultures of industrial interest. TaqMan chemistry was used to quantify down to 1 µg/L dry weight of S. almeriensis cells, as well as to detect the presence of other concentrated microalgae cultures. A simple direct PCR approach was also investigated to avoid classic DNA extraction and to reduce total experiment time to approximately 2 hours. The objective was to design strain-specific tools able to confirm and quantify the presence of different strains in any microalgae culture so as to achieve maximal productivity and quality of the produced biomass

A review on the status of protein nutrition of Argentine penaeoid shrimp: Comparison and contrasts within the Penaeidae

Protein is the major and the most expensive ingredient in shrimp feeds, as well as a growth limiting nutrient. This paper reviews the results of investigations designed to understand the protein nutrition in the most abundant penaeoid species in the Argentine Sea, Pleoticus muelleri Bate, 1888 and Artemesia longinaris Bate, 1888. One of the main obstacles to culture these species is the inadequate knowledge of their nutritional requirements. The present review focuses on applied nutrition of protein, protein sources in feed, and apparent digestibility. Also considered are digestive proteinase activity in relation to developmental stages and molting cycle, amino acid requirements, and optimal protein levels measured by growth responses. These results are compared with those obtained for other penaeoid species. This review provides a better understanding of feeding preferences and the formulation of suitable feeds for shrimp, which is essential to optimize the use of ingredients and reduce feed costs.Pleoticus muelleri Bate, 1888 and Artemesia longinaris Bate, 1888. One of the main obstacles to culture these species is the inadequate knowledge of their nutritional requirements. The present review focuses on applied nutrition of protein, protein sources in feed, and apparent digestibility. Also considered are digestive proteinase activity in relation to developmental stages and molting cycle, amino acid requirements, and optimal protein levels measured by growth responses. These results are compared with those obtained for other penaeoid species. This review provides a better understanding of feeding preferences and the formulation of suitable feeds for shrimp, which is essential to optimize the use of ingredients and reduce feed costs.Fil: Fenucci, Jorge Lino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Díaz, Ana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Acien Fernandez, Francisco Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Photosynthesis Monitoring in Microalgae Cultures Grown on Municipal Wastewater as a Nutrient Source in Large-Scale Outdoor Bioreactors

Microalgae cultures were used for a WW treatment to remediate nutrients while producing biomass and recycling water. In these trials, raceway ponds (RWPs; 1 and 0.5 ha) were located next to a municipal (WW) treatment plant in Mérida, Spain. The ponds were used for continuous, all-year-round microalgae production using WW as a source of nutrients. Neither CO2 nor air was supplied to cultures. The objective was to validate photosynthesis monitoring techniques in large-scale bioreactors. Various in-situ/ex-situ methods based on chlorophyll fluorescence and oxygen evolution measurements were used to follow culture performance. Photosynthesis variables gathered with these techniques were compared to the physiological behavior and growth of cultures. Good photosynthetic activity was indicated by the build-up of dissolved oxygen concentration up to 380% saturation, high photochemical yield (Fv/Fm = 0.62–0.71), and relative electron transport rate rETR between 200 and 450 μmol e− m−2 s−1 at midday, which resulted in biomass productivity of about 15–25 g DW m−2 day−1. The variables represent reliable markers reflecting the physiological status of microalgae cultures. Using waste nutrients, the biomass production cost can be significantly decreased for abundant biomass production in large-scale bioreactors, which can be exploited for agricultural purposes