Seaweeds
Parimelazhagan Thangaraj in Phytomedicine, 2020
Pigments facilitate the phototrophs to trap light as energy, one such abundant pigment is chlorophyll, which has a very close relation with the common green pigment found commonly in all the autotrophs. The next major seaweed pigment is an orange colored pigment viz. carotenoids that play a harmonizing role in photosynthesis by transferring electrons onto chlorophyll. The chlorophyll and carotenoid content in macro algae differs according to the varying levels of UV intensity (Yuan 2007). These pigments exhibit anti-oxidant properties (Aikaterini et al. 2018; Lordan et al. 2011; Yuan 2007).
Dunaliella salina
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
Dunaliella salina was first described by Felix Dunal in 1838 and Clara Hamburger in 1905 (Teodoresco 1905; Jaenicke 1998; Oren 2005). They described D. salina as a eukaryotic unicellular microalgae that becomes red-colored when it thrives in the brines of salt lakes and salterns around the halophilic habitats of the French Mediterranean coast (Teodoresco 1905). Presently this genus has been reported in several hypersaline environments in various parts of the world. While Lerche (1937) conducted studies on development and reproduction in Dunaliella, it was Teodoresco (1866–1949) who named D. salina in honor of F. Dunal. Mil’ko (1963) and Massyuk (1966) were the first to propose that D. salina would be an ideal commercial source of natural β-carotene, and they conducted several trials of mass culture of this alga in Ukraine (Massyuk and Abdulla 1969; Borowitzka and Borowitzka 1988). Ben-Amotz et al. (1982) proposed this alga as source of glycerol as well. Actually, Dunaliella salina has been identified in all the hypersaline environments worldwide, where other oxygenic phototrophs fail to grow (Oren 2005). This flagellate alga accumulate the highest amount of β-carotene per cell of any organism, measuring up to 14% on the basis of dry weight (Mil’ko 1963; Aasen et al. 1969; Borowitzka and Borowitzka 1990). It is known that D. salina accumulates around 102 mg of β-carotene per 100 g, while carrots only accumulate 3 mg (USDA National Nutrient Database for Standard Reference Release 18 USA) (Al-Muhteseb and Emeish 2015). β-carotene from D. salina is currently produced on a commercial and pilot scale in several countries, among them Australia, Israel, the United States, India, China, and Spain. In fact, the market for natural β-carotene is increasing worldwide (Figure 14.2).
Bacteria
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
Some bacteria have the capability of synthesizing all of their cellular carbon compounds from carbon dioxide or carbonate and their other nutritional requirements from nonorganic sources, using energy to do so derived either from (A) the oxidation of one of the following nonorganic chemicals: ferrous iron, ammonium, methane, or inorganic sulfur (these organisms are called chemoautotrophs or autotrophs), or (B) light (these organisms are called photoautotrophs or phototrophs).
Biofilm diversity, structure and matrix seasonality in a full-scale cooling tower
Published in Biofouling, 2018
L. Di Gregorio, R. Congestri, V. Tandoi, T. R. Neu, S. Rossetti, F. Di Pippo
The highest bacterial biodiversity was recorded in winter (Bi-Wi, Figure 1C), when there was a dominance of Alphaproteobacteria (49.6%), with the Bradyrhizobiaceae (20.7%), Sphingomonadaceae (7.3%) and Hyphomicrobiaceae (5.7%) well represented. The Betaproteobacteria were also abundant (9.6%), the most common of which were Comamonadaceae (7.6%). Phototrophs comprised Cyanobacteria (5.5%), primarily the oscillatorialean genera Microcoleus and Leptolyngbya, along with the chroococcalean Pleurocapsa and Chroococcus (Figure 2). Taxonomic assignment of chloroplast OTUs was performed using the BLAST classifier, which revealed the occurrence of the green algae Vischeria sp., Kirchneriella sp. and Scenedesmus sp. Light microscopy and SEM observations revealed the highest species richness of diatoms in winter when they dominated the phototrophic biofilm fraction, with species attributable to the genera Navicula, Nitzschia and Surirella predominant. Amphora sp., Cymbella sp. and Pinnularia sp. were also present (Figure 3A–C).
Short-term succession of marine microbial fouling communities and the identification of primary and secondary colonizers
Published in Biofouling, 2019
Raeid M. M. Abed, Dhikra Al Fahdi, Thirumahal Muthukrishnan
The total biomass, abundance of macrofoulers, chl a and bacterial counts showed a significant gradual increase with time (p < 0.001, ANOVA), reaching their highest values after 28 days deployment. The total biomass increased from 0.17 ± 0.02 mg cm−2 in day 1 to 11.06 ± 3.0 mg cm−2 in day 28 (Figure 1A). The percentage coverage of macrofoulers was <5% until day 7, but then rapidly increased to 21 ± 2.9% of the total surface area of each panel after 28 days (Figure 1B). Chl a concentration, indicative of the abundance of phototrophs, increased from 0.08 ± 0.02 to 0.68 ± 0.2 µg g−1 within the first five days of deployment (Figure 1C). A clear drop in chl a concentrations was observed at day 7, most likely due to increasing grazing activities, after which a sharp increase was observed. Bacterial density showed a steady increase over time, reaching a total of 4.3 × 107 cells g−1 after 28 days (Figure 1D).
High-throughput method development for in-situ quantification of aquatic phototrophic biofilms
Published in Biofouling, 2022
Maria Papadatou, Mollie Knight, Maria Salta
Aquatic phototrophic biofilms are mixed microbial conglomerations formed and attached to submerged solid surfaces, typically composed by light-driven autotrophs and heterotrophs that are surrounded and stabilized by self- producing extracellular polymeric substances (EPS) (Hoagland et al. 1993; Cooksey and Wigglesworth-Cooksey 1995; Landoulsi et al. 2011). In a nutshell, at the top biofilm phototrophic layer, oxygenic photoautotrophs are prevailing, whilst the internal part of the biofilms consists of heterotrophs (bacteria, protozoa, fungi) and anoxygenic phototrophs (Roeselers et al. 2007; Bharti et al. 2017). Oxygenic photoautotrophs (primary producers) primarily consist of diatoms, green algae, and cyanobacteria that possess photosynthesizing components enabling them to use light energy and reduce carbon dioxide, thus producing oxygen and organic substrates (Roeselers et al. 2007, 2008).