Haloarchaea are halophilic microorganisms belonging to the archaea domain that inhabit salty environments (mainly soils and water) all over the world. Most of the genera included in this group can ...produce carotenoids at significant concentrations (even wild-type strains). The major carotenoid produced by the cells is bacterioruberin (and its derivatives), which is only produced by this kind of microbes and few bacteria, like
. Nevertheless, the understanding of carotenoid metabolism in haloarchaea, its regulation, and the roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. Besides, potential biotechnological uses of haloarchaeal pigments are poorly explored. This work summarises what it has been described so far about carotenoids from haloarchaea and their production at mid- and large-scale, paying special attention to the most recent findings on the potential uses of haloarchaeal pigments in biomedicine.
A greater insight on the control of the interactions between microalgae and other microorganisms, particularly bacteria, should be useful for enhancing the efficiency of microalgal biomass production ...and associated valuable compounds. Little attention has been paid to the controlled utilization of microalgae-bacteria consortia. However, the studies of microalgal-bacterial interactions have revealed a significant impact of the mutualistic or parasitic relationships on algal growth. The algal growth, for instance, has been shown to be enhanced by growth promoting factors produced by bacteria, such as indole-3-acetic acid. Vitamin B12 produced by bacteria in algal cultures and bacterial siderophores are also known to be involved in promoting faster microalgal growth. More interestingly, enhancement in the intracellular levels of carbohydrates, lipids and pigments of microalgae coupled with algal growth stimulation has also been reported. In this sense, massive algal production might occur in the presence of bacteria, and microalgae-bacteria interactions can be beneficial to the massive production of microalgae and algal products. This manuscript reviews the recent knowledge on the impact of the microalgae-bacteria interactions on the production of microalgae and accumulation of valuable compounds, with an emphasis on algal species having application in aquaculture.
In this study, the effect of abiotic stress on the acidophilic eukaryotic microalga, Coccomyxa onubensis, was analyzed for the production of lutein and PUFAs (polyunsaturated fatty acids). It grows ...autotrophically at a pH of 2.5. It showed a growth rate of 0.30 d−1, and produced approximately 122.50 mg·L−1·d−1 biomass, containing lipids (300.39 mg g−1dw), lutein (5.30 mg g−1dw), and β-carotene (1.20 mg g−1dw). The fatty acid methyl ester (FAME) fraction was 89.70 mg g−1dw with abundant palmitic acid (28.70%) and linoleic acid (37.80%). The addition of 100 mM NaCl improved the growth rate (0.54 d−1), biomass productivity (243.75 mg·L−1·d−1), and lipids accumulation (416.16 mg g−1dw). The microalga showed a lutein content of 6.70 mg g−1dw and FAME fraction of 118.90 mg g−1dw; 68% of the FAMEs were PUFAs. However, when 200–500 mM salt was added, its growth was inhibited but there was a significant induction of lutein (up to 7.80 mg g−1dw). Under continuous illumination with PAR (photosynthetically active radiations) +UVA (ultraviolet A, 8.7 W m−2), C. onubensis showed a growth rate of 0.40 d−1, and produced 226.3 mg·L−1·d−1 biomass, containing lipids, (487.26 mg g−1dw), lutein (7.07 mg g−1dw), and FAMEs (232.9 mg g−1dw); 48.4% of the FAME were PUFAs. The illumination with PAR + UVB (ultraviolet B, 0.16 W m−2) was toxic for cells. These results indicate that C. onubensis biomass is suitable as a supplement for functional foods and/or source of high added value products.
is known to be a natural source of antioxidants for numerous applications. In this study, an oleoresin rich in carotenoids extracted by supercritical CO
treatment of
was extensively characterized for ...its antioxidant capacity. Carotenoid content, fatty acid profile, total phenol content, antioxidant capacity, and viscosity of the oleoresin were determined with the aim of ascertaining the potential of the oleoresin in terms of its antioxidant content for food applications. The oleoresin contained 96.22 mg/g of total astaxanthin (which includes free astaxanthin and astaxanthin esters) and mostly included unsaturated fatty acids (~78% of total fatty acids). High total phenol content and ferric reducing antioxidant potential indicated high antioxidant capacity, but oxygen radical absorbance capacity was lower compared to the oleoresin samples obtained from other species. The oleoresin was a non-Newtonian fluid since it had shear-thinning (pseudoplastic) and shear-thickening (dilatant) flow. Therefore, the
oleoresin is a potential alternative in developing functional ingredients for designing healthy food products. To the best of our knowledge, this is the first study that has reported an extensive characterization of the antioxidant properties of a microalgal oleoresin obtained by means of supercritical CO
fluid extraction.
The use of microalgae cultures has been proposed as an innovative method to remove CO2 from biogas. However, the design of a large-scale installations requires the identification of key operational ...parameters and the determination of the maximum treatment capacity of the system. The aim of this work is to advance in that direction, using mathematical modelling. A model was developed, considering a system composed of a bubble column connected with an open photobioreactor. Simulations were carried out to evaluate the operation of a potential large-scale system. Results show that biogas upgrading would be feasible at large scales. At a biogas treatment capacity of 0.12 m3 d−1 per m3 reactor, an upgraded biogas with less than 3 and 1% of CO2 and O2, respectively, could be obtained. Under such condition, more that 80% of the inorganic carbon from the biogas would be transformed into biomass. Considering the low volumetric capacity of the system, its feasibility is expected to be determined by the biomass economic value.
•Studied system can provide an upgraded biogas quality fulfilling most regulations.•Imposed conditions will define fate of CO2: desorption to atmosphere or fixation.•System has lower biogas treatment capacity per m2 than traditional technologies.•Feasibility will be determined by application of an industrial ecology approach.
We present the case of a 63-year-old woman who developed dermatomyositis after hematopoietic stem cell transplantation. Anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibodies were ...positive and pulmonary involvement was severe and progressive. In addition, we also report that the patient's sister and donor also developed dermatomyositis. She had positive anti-PL7 antibodies and negative anti-MDA5 antibodies. The occurrence of autoimmune diseases after allogeneic hematopoietic stem cell transplantation is infrequent and difficult to interpret due to the reconstitution of the immune system and the multifactorial origin of most of these diseases. To our knowledge, this is the first described case of a hematopoietic progenitor transplant donor and recipient developing dermatomyositis. These findings make us wonder whether the dermatomyositis in this case is due to a shared genetic predisposition or to the donor's disease developing in the recipient.
Carotenoids are the most common pigments in nature and are synthesized by all photosynthetic organisms and fungi. Carotenoids are considered key molecules for life. Light capture, photosynthesis ...photoprotection, excess light dissipation and quenching of singlet oxygen are among key biological functions of carotenoids relevant for life on earth. Biological properties of carotenoids allow for a wide range of commercial applications. Indeed, recent interest in the carotenoids has been mainly for their nutraceutical properties. A large number of scientific studies have confirmed the benefits of carotenoids to health and their use for this purpose is growing rapidly. In addition, carotenoids have traditionally been used in food and animal feed for their color properties. Carotenoids are also known to improve consumer perception of quality; an example is the addition of carotenoids to fish feed to impart color to farmed salmon.
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