BACKGROUND: The novelty of this work is the estimation of the fuel properties of biodiesel, a comparison study with conventional sources of biodiesel commonly used as feedstock, and an investigation for meeting the requirements of the standard specifications for this fuel produced by six strains of microalgae (three cyanobacteria, two green algae and one diatom), cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity and biofuel quality were the criteria for species selection.

Glucose is the substrate most widely used as exogenous carbon source for heterotrophic cultivation of cyanobacteria. Due to limited information about the use of different carbohydrates as carbon sources to support cyanobacterial heterotrophic metabolism, the objective of this work was to evaluate different monosaccharides (arabinose, fructose, galactose, glucose, mannose and xylose), disaccharides (lactose, maltose, sucrose and trehalose) and polysaccharides (carboxymethylcellulose, cassava starch, Hi-maize(®), maltodextrin Corn Globe 1805(®) and xylan) as exogenous carbon source for heterotrophic culture of cyanobacterium Phormidium sp. The batch cultivation using fructose as organic carbon source resulted in the highest (p < 0.05) cell biomass (5,540 mg/L) in parallel with the highest (p < 0.05) substrate yield coefficient (0.67 mg(biomass)/mg(fructose)). Mannose was the carbon source with the highest (p < 0.05) substrate consumption rate (3,185.7 mg/L/day) and maltodextrin was the carbohydrate with major potential to produce biomass (1,072.8 mg(biomass)/L/day) and lipids (160.8 mg(lipids)/L/day). Qualitatively, the fatty acid profiles of the lipid extract from Phormidium sp. showed predominance of saturated chains for the cultures grown with most of the carbon sources, with the exception of the ones grown with xylose and maltodextrin.

have demonstrated that atrazine has toxic effects in algae, aquatic plants, aquatic insects, fishes and mammals. Owing to the toxicity and persistence of atrazine in the environment, the search of microbial strains capable of degrading it is fundamental to the development of bioremediation processes, as corrective tools to solve the current problems of the irrational use of agrochemicals. This work aimed the isolation and identification of atrazine degrading bacteria from rizospheric soil, as well as the evaluation of their degradation capacity. Two different atrazine degrading bacteria were isolated and identified as belonging to the genera Arthrobacter and Corynebacterium. Arthrobacter sp. proved to be a better atrazine degrader by the appearance of transparent halos around the colonies when atrazine (0.1 g L −1 ) was the sole carbon and nitrogen source in the medium. In liquid medium, higher specific growth rate (0.0499 hour −1 ) was observed with Arthrobacter sp. when sodium citrate (1 g L −1 ) was an additional source of carbon.

This study aimed to evaluate third generation biodiesel production by microalgae Phormidium autumnale using cassava processing wastewater as a platform. Experiments were , respectively. The composition of this oil is predominantly saturated (60 %) and monounsaturated (39 %), resulting in a biodiesel that complys with U.S., European and Brazilian standards. The technological route developed indicates potential for sustainable production of bulk oil and biodiesel, through the minimization of water and chemical demands required to support such a process.

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