Chlamydomonas acidophila LAFIC-004 is an acidophilic strain of green microalgae isolated from coal mining drainage. In the present work, this strain was cultivated in acidic medium (pH 3.6) under phototrophic, mixotrophic, and heterotrophic regimes to determine the best condition for growth and lipid production, simultaneously assessing possible morphological and ultrastructural alterations in the cells. For heterotrophic and mixotrophic treatments, two organic carbon sources were tested: 1 % glucose and 1 % sodium acetate. Lipid content and fatty acid profiles were only determined in phototrophic condition. The higher growth rates were achieved in phototrophic conditions, varying from 0.18 to 0.82 day. Glucose did not result in significant growth increase in either mixotrophic or heterotrophic conditions, and acetate proved to be toxic to the strain in both conditions. Oil content under phototrophic condition was 15.9 % at exponential growth phase and increased to 54.63 % at stationary phase. Based on cell morphology (flow cytometry and light microscopy) and ultrastructure (transmission electron microscopy), similar characteristics were observed between phototrophic and mixotrophic conditions with glucose evidencing many lipid bodies, starch granules, and intense fluorescence. Under the tested conditions, mixotrophic and heterotrophic modes did not result in increased neutral lipid fluorescence. It can be concluded that the strain is a promising lipid producer when grown until stationary phase in acidic medium and under a phototrophic regime, presenting a fatty acid profile suitable for biodiesel production. The ability to grow this strain in acidic mining residues suggests a potential for bioremediation with production of useful biomass.

Polyhydroxyalkanoates (PHAs) are a class of biopolymers with numerous applications, but the high cost of production has prevented their use. To reduce this cost, there is a prospect for strains with a high PHA production and the ability to grow in low-cost by-products. In this context, the objective of this work was to evaluate marine bacteria capable of producing PHA. Using Nile red, 30 organisms among 155 were identified as PHA producers in the medium containing starch, and 27, 33, 22 and 10 strains were found to be positive in media supplemented with carboxymethyl cellulose, glycerol, glucose and Tween 80, respectively. Among the organisms studied, two isolates, LAMA 677 and LAMA 685, showed strong potential to produce PHA with the use of glycerol as the carbon source, and were selected for further studies. In the experiment used to characterize the growth kinetics, LAMA 677 presented a higher maximum specific growth rate (µmax = 0.087 h−1) than LAMA 685 (µmax = 0.049 h−1). LAMA 677 also reached a D-3-hydroxybutyrate (P(3HB)) content of 78.63% (dry biomass), which was 3.5 times higher than that of LAMA 685. In the assay of the production of P(3HB) from low-cost substrates (seawater and biodiesel waste glycerol), LAMA 677 reached a polymer content of 31.7%, while LAMA 685 reached 53.6%. Therefore, it is possible to conclude that the selected marine strains have the potential to produce PHA, and seawater and waste glycerol may be alternative substrates for the production of this polymer.

A review of the dinoflagellate genus Alexandrium occurring in Brazilian coastal waters is presented based on both published information and new data. Seven Alexandrium species have been recorded from Brazil so far: Alexandrium catenella, Alexandrium fraterculus, Alexandrium gaardnerae, Alexandrium kutnerae, Alexandrium tamiyavanichi, Alexandrium tamutum, and Alexandrium sp. While A. gaardnerae and A. kutnerae were identified based only on morphological characteristics, phylogenetic analysis (ITS and LSU rDNA) were performed for the remaining species based on cultures and/or field populations. Monoclonal cultures of the analyzed species were isolated from field samples obtained from Bahia (A. tamiyavanichi, two strains), Rio de Janeiro (A. tamutum, three strains; Alexandrium sp., two strains), Santa Catarina (A. fraterculus, one strain), and Rio Grande do Sul (Alexandrium tamarense, three strains). This is the first record of A. tamutum for the South Atlantic. In addition, molecular data for Brazilian strains of A. fraterculus are presented for the first time, as well as sequences from the ITS region for A. catenella (previously reported as A. tamarense) from Brazilian coastal waters. The morphological characters of the three species corresponded to those typically recorded in the literature and their identification was confirmed by molecular analysis. Based on the LSU rDNA and ITS regions, the three strains of A. catenella showed a high degree of similarity with strains from Southern Chile and North America. The implications and limitations of these findings for the monitoring protocols within the global and regional context are discussed.

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The purpose of this study was to describe the composition and occurrence of potentially toxic and harmful species of thecate dinoflagellates in cultured shellfish, located at Armação do Itapocorói (AI) and Praia Alegre (PA) in the municipality of Penha, SC -Brazil. Water samples were collected and environmental parameters (salinity, water temperature and depth of Secchi disk) were determined weekly between April 2007 and April 2008 at two sites by a monitoring program maintained by the Laboratory for the Study of Harmful Algae, CTTMar, UNIVALI. The identification of the organisms was made through an Olympus microscope, model BX41 with up to 1000x. During the sampling period, we identified 21 species of thecate dinoflagellates potentially toxic and harmful in the genus Alexandrium, Ceratium, Dinophysis and Prorocentrum. The species P. obtusum (86%), D. acuminata (78.5%) and P. micans (72%) were very frequent throughout the period in the two sample points. The point with highest species richness was the AI, with 14 species, and the PA had the lowest richness with only two species. Most samples were considered rare relative to the abundance of thecate dinoflagellates compared to the presence of harmful microalgae, but during the month of September 2007, were considered abundant, during which there was a bloom of D. acuminata. The similarity between the two points throughout the sampling period reached a high coefficient (86%), and between the months examined, June 2007 showed the lowest similarity (10%) and July 2007 the greatest similarity recorded (91%). The composition and distribution of thecate dinoflagellates during the study showed that the existence of a dynamic community structure could be used as a tool to aid the monitoring of harmful algae mariculture activity in this region.