Microalgae contain high levels of proteins, carbohydrates, and lipids, and have found a useful application in enhancing the nutritional value of foods. These organisms can also synthesize long‐chain fatty acids in the form of triacylglycerols, such as α‐linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linolenic acid (LA), γ‐linolenic acid (GLA) and arachidonic acid (AA). The aim of this study was to determine the chemical composition and measure protein, carbohydrates, fibers, lipids as well as the fatty acids composition of six microalgae species with potential application in the food industry. Two freshwater species, Chlorella vulgaris and Spirulina platensis, and four marine species, Nannochloropsis oculata, Nannochloropsis gaditana, Porphyridium cruentum, and Phaeodactylum tricornutum, were used in the experiments. Intracellular protein was the most prominent algal component (42.8–35.4 %), followed by carbohydrate + fiber (32.3–28.6 %), and lipids (15.6–5.3 %). N. gaditana is rich in saturated fatty acids, mainly palmitic acid (5.1 g/100 g), while the cells of S. platensis and C. vulgaris algae are abundant in GLA (1.9 g/100 g) and ALA (2.8 g/100 g) acids, respectively. P. cruentum differs from other algae, because it contains a large amount of AA (3.7 g/100 g). The marine microorganisms N. oculata and P. tricornutum are also a source of essential long‐chain polyunsaturated fatty acids (LC‐PUFA‐ɷ3), mainly composed of EPA and DHA. Our results suggest that the freshwater species C. vulgaris and S. platensis are attractive nutritional supplements because of their low fiber and high protein/carbohydrate contents, while the marine species P. tricornutum and N. oculata can enrich foods with LC‐PUFA‐ω3, because of their favorable ω3/ω6 ratio.

Recebido em 12/12/03; aceito em 14/9/04; publicado na web em 4/2/05 APPLICATION OF LIPASES FOR WASTEWATER TREATMENT CONTAINING HIGH LEVELS OF LIPIDS. The process of anaerobic digestion has been greatly developed during the last decades for the treatment of wastewater from food industries as for example, wastewaters from sugar and starch manufacturing and from breweries. However, for wastewaters which contain high amounts of fats and proteins, such as those from slaughterhouses and dairies, anaerobic digestion was found to be troublesome, due to the potential of sludge flotation, the formation of scum layers of lipids at the surface of the reactor, which are not digested and the toxicity of the intermediate compounds (long chain fatty acids) generated during the anaerobic digestion of the wastewater. The addition of hydrolytic enzymes, such as lipases prior to the anaerobic digestion can minimize these problems. In this work, this strategy is reviewed and the technical issues that must be considered in determining its feasibility are discussed.Keywords: wastewater; lipids; lipase and enzymatic treatment. INTRODUÇÃOA adoção de um maior rigor nos padrões de descarte de águas residuárias tem motivado a realização de pesquisas, cujo objetivo é reduzir o impacto ambiental, especialmente em efluentes contendo elevados teores de lipídeos, como os provenientes de laticínios, matadouros e avícolas, enlatados, extração de óleos, entre outros. A Política Nacional de Recursos Hídricos, instituída pela Lei Federal n° 9.433 de 8 de janeiro de 1997 trata da cobrança pelo uso dos corpos d'água para o lançamento de despejos líquidos.Os lipídeos contidos nesses efluentes, além de representarem uma perda industrial importante, interferem negativamente nos Sistemas de Tratamento de Efluentes. Elevadas concentrações de lipídeos resultam na formação de lodos com diferentes características físicas e reduzida atividade hidrolítica devido à flotação dessa biomassa, aumento do tempo de retenção hidráulica desses efluentes nas lagoas de estabilização, redução da capacidade de aeradores e elevada demanda de produtos floculantes 1 . Dentro deste contexto, processos alternativos vêm sendo utilizados na redução da concentração de lipídeos contidos nesses efluentes por meio de ação de enzimas, particularmente lipases. Essas enzimas apresentam uma importância particular, pelo fato de hidrolisarem especificamente óleos e gorduras, o que pode ser de grande interesse para o tratamento de efluentes com alto teor de gordura. As lipases (triacilglicerol acil hidrolases, E.C.3.1.1.3) compreendem um grupo de enzimas hidrolíticas que atuam na interface orgânica-aquosa, catalisando a hidrólise de ligações éster-carboxílicas, presentes em acilgliceróis 2 . A sua utilização reduz os níveis de sólidos suspensos e lipídeos, o que possibilita melhores condições de operação no tratamento anaeróbio e desobstrui filmes de óleos em tubulações, resultando no aumento da vida útil dos equipamentos.Além disso, esse tratamento apresenta algumas vantagens, tais como a e...

This work aimed at evaluating the conditions of growth and the recovery of total carotenoids produced by Sporidiobolus salmonicolor (CBS 2636). Optimization of carotenoid production was achieved by experimental design technique. A Plackett-Burman design was used, followed by a complete second-order design, to optimize the concentration of total carotenoids in a conventional medium. Maximum concentration of 1,019 μg l −1 of total carotenoids was obtained in a medium containing 40 g l −1 glucose, 10 g l −1 malt extract, and 14 g l −1 peptone, at 180 rpm, 25°C, and initial pH of 4.0. So far, no previous systematic study using microorganisms of the genus Sporobolomyces (formerly Sporidiobolus) for production of carotenoids has been reported. In this study, very good yields of carotenoids (1 mg l −1 ) could be obtained after optimization of fermentation medium and operation conditions.

Lipids-rich wastewater was partial hydrolyzed with porcine pancreas lipase and the efficiency of the enzymatic pretreatment was verified by the comparative biodegradability tests (crude and treated wastewater

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The increasing demand for carotenoids by industries has drawn attention to their bio-production. Since pigments are intracellular, extraction steps are then needed after cell cultivation. In this work, different strategies for extraction of carotenoid pigments from Sporidiobolus salmonicolor (CBS 2636) were studied. Different solvents (dimethyl sulfoxide, petroleum ether, hexane, ethyl acetate, chloroform, and acetone), liquid N 2 , and diatomaceous earth were used to disrupt the cell and thus release the intracellular carotenoids. The results of this study showed that when multiple solvents were used, a synergistic effect on the extent of carotenoids recovery was obtained. Maximum concentration of total carotenoids (913 μg/L) was obtained in the treatment using liquid N 2 and dimethyl sulfoxide to disrupt the cell, followed by the extraction with a solution of acetone/methanol (7:3, v/v).

BACKGROUND: The increasing industrial demand for carotenoids has aroused interest in their bio-production, and the need to reduce production costs has encouraged the use of low cost industrial substrates, such as agroindustrial residues. Thus the objective of this research was the bio-production of carotenoids by Sporidiobolus salmonicolor using agro-industrial substrates (corn steep liquor and sugarcane molasses), pre-treated with acids (sulphuric and phosphoric).

Current models that describe the extension of fungal hyphae and development of a mycelium either do not describe the role of vesicles in hyphal extension or do not correctly describe the experimentally observed profile for distribution of vesicles along the hypha. The present work uses the n-tanks-in-series approach to develop a model for hyphal extension that describes the intracellular transport of nutrient to a sub-apical zone where vesicles are formed and then transported to the tip, where tip extension occurs. The model was calibrated using experimental data from the literature for the extension of reproductive aerial hyphae of three different fungi, and was able to describe different profiles involving acceleration and deceleration of the extension rate. A sensitivity analysis showed that the supply of nutrient to the sub-apical vesicle-producing zone is a key factor influencing the rate of extension of the hypha. Although this model was used to describe the extension of a single reproductive aerial hypha, the use of the n-tanks-in-series approach to representing the hypha means that the model has the flexibility to be extended to describe the growth of other types of hyphae and the branching of hyphae to form a complete mycelium.