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As the shift toward environmentally renewable resources occurs algae cultivation for lipids, co-products and biomass, as a source of antioxidants, food, livestock feed, cosmetics and renewable fuel feedstock is of continuing growing interest. In this work we describe the profile and content of carotenoids and lipids of a promising microalgae identified as a Chlorococcum sp. Experiments were performed in environmental photobioreactors (ePBRs) and incubators under constant, low and high intensity irradiance. Metabolite, lipid, and carotenoid profiles determination was done during the transition from green vegetative cells to the highly pigmented carotenogenic cells. The objective of this work was to gather a better understanding of carbon allocation and lipid synthesis/remodeling events of the Chlorococcum sp. strain under increased photooxidative stress and other environmental stressors. This biochemical basis of the relationship between stress inducing conditions, carotenoid synthesis, high lipid content and fatty acid composition is beneficial for further increasing the productivity and economic development of this Chlorococcum strain. [ABSTRACT FROM AUTHOR]

The growing demand for large-scale sustainable, low-cost production of polyunsaturated fatty acids (PUFAs), carotenoids, and other high-value bioproducts has led to increased research in prospective microalgal species within the past several decades. The oleaginous marine microalga Nannochloropsis salina has received attention for its high oil yield (37-60% wt.) and production of the dietary PUFA ω-3 eicosapentaenoic acid (EPA). Marine microalgae found in temperate waters are subject to dynamic temperature fluctuations, which require mechanisms for temperature modulation. The incorporation of unsaturated fatty acids into membrane lipid pools is particularly important for maintaining membrane fluidity and cellular structure; therefore, the composition and content of membrane lipid pools is thought to be heavily regulated by temperature. Previous research has shown that N. salina grown under "cold stress" (=10°C below optimal temperature) results in both increased lipid production and desaturation of fatty acids. Reduced biomass productivity is a consequence of cold stress; however, regulation of cold stress through sinusoidal temperature control has been shown to reduce the effect on growth. Here, we demonstrate the effects of cold stress under 12:12 hr sinusoidal control on N. salina using four temperature regimes: 5°C, 10°C, 15°C and 20°C that all increase to 25°C during peak light intensity, while the control is maintained at a constant temperature of 25°C. Physiological stress is determined through growth rate, chlorophyll fluorescence and dissolved oxygen measurements. Metabolomes were sequenced and quantified using GC TOF MS, and the results were analyzed for statistical significance using MetaboAnalyst V3.0. In addition, a pathway enrichment analysis was performed using VANTED V2.6.3 that reveals depletions in TCA cycle intermediates, particularly acetyl-CoA pools, under cold stress. Total fatty acid (TFA) content is quantified using fatty acid methyl ester analysis, and increases in both the amount and desaturation of fatty acid pools are observed at lower temperatures. Whole lipidome profiling is performed using FT ICR MS, and at reduced temperatures there is an increased proportion of EPA in both triacylglycerol and membrane lipid pools. [ABSTRACT FROM AUTHOR]

The research investigates two North American microalgae. One species of Haematococus pluvialis and two species of Coelastrella were analyzed. The goal is to determine which health beneficial antioxidants, otherwise known as carotenoids, each species produce when stressed. The species of algae were stressed using fluorescent lighting and an altered media. The media is deprived of nitrogen, therefore reducing carbon fixation. The media has never before been used with these specific species of algae, proving this research unique. The algae were stressed and observed for 12 days. The carotenoid profile presented lutein as the most abundant antioxidant produced in all three species. Lutein can be used to prevent several eye diseases. The results of the study may provide a more environmentally friendly source for antioxidants that have been proven beneficial to human health. [ABSTRACT FROM AUTHOR]

The present study was conducted to analyze the biomass and lipid accumulations in the red alga Galdieria sulphuraria under mixotrophic conditions. It has also proven that G. sulphuraria to be useful for biofuel and other valuable compound production. In recent studies, it has been seen that sugar beet molasses and glucose yielded higher biomass and lipid content. However, these studies have not led to the analysis of the role of other sugars as the carbon sources. The first goal of this research effort is to evaluate the biomass and total fatty acid, lipid and Calvin cycle in different sugars as carbon sources. According to this study the specific growth rate was higher when the cells were grown under mixotrophic culture condition on equal molar concentration of C atoms from glucose, fructose, sucrose and glycerol. However, maximum biomass production was achieved in the cultures grown on glucose and glycerol as the carbon sources. These results showed that glycerol is the best carbon source for the Galdieria growth under mixotrophic condition. Furthermore, we present the amount of total lipids and fatty acids and metabolism in the mixotrophic culture conditions. [ABSTRACT FROM AUTHOR]

Oleaginous microalga Nannochloropsis salina is known for its potential as a source of renewable bio-fuel due to its high oil yield. In addition N. salina is also a source for the value added polyunsaturated fatty acids (PUFAs) with relative high level of n-3 eicosapentaenoic acid (EPA). Lipid productivity and composition of oleaginous microalgae is variable and dependent on strain selection and environmental growth conditions. When environmental conditions lead to suboptimal temperatures aka: "cold stress" one of the response of the organism is to increase PUFAs metabolism leading to an increase in membrane fluidity decrease the negative impact that near freezing temperatures have on cellular components. In this study we report on the effect of suboptimal temperatures from 20oC to 5oC on the growth, physiological measurements and fatty acid profile of N. salina. In addition we investigated the fatty acid composition of different lipid species, lipid gene expression and how metabolic alterations and remodeling occur in various lipid pools with specific interest in TAGs. [ABSTRACT FROM AUTHOR]

American Heart Society recommends consumption of 1g Omega-3 fatty acids per day to prevent heart diseases. The oleaginous marine microalga Nannochloropsis salina has received attention for its high oil yield (37-60% wt.) and production of the dietary polyunsaturated fatty acids, ω-3 eicosapentaenoic acid (EPA). The incorporation of unsaturated fatty acids into membrane lipid pools is particularly important for maintaining membrane fluidity and cellular structure at suboptimal temperatures. We found that N. salina grown under "cold stress" (≥10°C below optimal temperature) results in increased desaturation of fatty acids. Here, we demonstrate the effects of cold stress under 16:8 hr day:night cycle on N. salina using four temperature regimes: 5°C, 10°C, 15°C and 25°C, where 25°C was used as control. Physiological stress was determined by measuring growth rate, chlorophyll fluorescence and dissolved oxygen measurements. Total lipids were measured using FAME analysis. Gene expression studies were carried out targeting the genes involved in Kennedy pathway for tri-acylglycerol (TAG) synthesis. We performed Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry to study the variation in different lipid classes under sub optimal temperatures. Metabolomics was carried out using GC TOF MS, and the results were analyzed for statistical significance using MetaboAnalyst V3.0. [ABSTRACT FROM AUTHOR]

The majority of the fuels we use in our vehicles and other equipment on a daily basis are nonrenewable. As a result, the world is going to eventually run out of supplies of fuels. In addition, the current fuel sources are environmentally unfriendly, releasing greenhouse gases into the atmosphere. Many alternatives to using natural reservoirs as sources of fuels have been exploited, among which, the use of algal feedstock as a source of biofuel has received enormous attention. Algal biofuel was studied for a long time, and has recently gained popularity again due to the global demand for transportation fuels, the greenhouse gas effects, and the energy security risks. Funded by the NSF, at Eastern, we are cultivating algae on an outdoor pilot unit--Algal Turf Scrubber®--in dairy manure effluent for wastewater treatment and sustainable biofuel production. Algae offer an inexhaustible source of energy, nutrients and raw materials. When microalgae are grown and harvested, the biomass obtained contains lipids, which can be converted into biodiesels through chemical transformations. One of the main difficulties in implementing the use of algae for biofuel on a wider scale, is the inefficient methods of lipid extraction, and the current methods used do not exhaustively extract all the lipids, and are costly, thereby making the wide scale production of algae not economically feasible compared to the current natural fuels being used. In this project I investigated ways to maximize the amount of lipids extracted and develop simple extraction procedures that do not require a lot of energy to successfully extract the lipids required for the production of the biofuels. I used Gas Chromatography - Mass Spectrometry to characterize the extracted lipids. In addition, I will also investigate how to utilize the remaining material after the extraction is completed. [ABSTRACT FROM AUTHOR]