https://www.massey.ac.nz/~ychisti/Biodiesel.pdf

Biodiesel from microalgae.

Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO 2 , N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products. This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.

/pdf/biofuels-from-microalgae-a-review-of-technologies-for-1t1wwr5e69.pdf

Biofuels from microalgae—A review of technologies for production, processing, and extractions of biofuels and co-products

https://www.massey.ac.nz/~ychisti/EPA%20Review.pdf

Recovery of microalgal biomass and metabolites: process options and economics

http://www.unece.lsu.edu/biofuels/documents/2008oct/bf08_15.pdf

Biodiesel from microalgae beats bioethanol.

Heterotrophic cultures of microalgae: Metabolism and potential products

Microalgae have been proposed as a CO2 removal option to contribute to climate change avoidance and problems coming from the use of fossil fuels. However, even though microalgae can be used to fix CO2 from air or flue gases, they do not permit long-term CO2 storage because they are easily decomposed. On the other hand, microalgae can contribute to an enhancement in human sustainability by producing biofuels as an alternative to fossil fuels in addition to the production of other useful chemicals and commodities. Moreover, microalgae can contribute to enhancing the sustainability of waste treatment processes, reducing the energy consumed, and improving the recycling of nutrients contained within them. This paper reviews the potential contribution of these processes and the existing knowledge in these areas.

Conversion of CO2 into biomass by microalgae: how realistic a contribution may it be to significant CO2 removal?

Microalgae are produced today for human and animal markets, as food-feed and source of active compounds. Microalgae can be also used in wastewater treatment and they has been proposed as biofuels source to reduce global warming problem. Whatever the final application of microalgae its production is based on the same principles as light availability, enough mass and heat transfer and adequate control of culture parameters. In this paper these principals are revised. Moreover, the production must be carried out at adequate scale using photobioreactors. Design of photobioreactor is determined by the final use of biomass and quality required. Different designs today used are revised, including last designs proposed, identifying his characteristics parameters and applications. In addition, the obligation of adequate control strategies is discussed. Finally, the bottlenecks for the scale-up of the different technologies and thus of microalgae production are summarized.

Photobioreactors for the production of microalgae

Mixotrophic growth of the eicosapentaenoic acid (EPA)producing diatom Phaeodactylum tricornutum UTEX640 was carried out in 1-L batch cultures under anexternal irradiance of 165 μmol photons m-2s-1 by supplementing the inorganic culture mediumwith glycerol The effect on the growth and the fattyacid profile was studied for different initialglycerol concentrations (0–01 M) The optimalglycerol concentration was 01 MA lag phase was observed at high glycerolconcentrations The present study also shows thatsuccessive additions of glycerol at 01M concentrationand using ammonium chloride as a nitrogen sourceremarkably increased the maximum biomass concentration(162 g L-1) and maximum biomass productivity(615 mg L-1 h-1) These values wererespectively 9 and 8-fold higher than in thephotoautotrophically grown control The level ofsaponifiable lipids in mixotrophically cultured cellswas significantly higher than in photoautotrophicallycultured cells and increased with the glycerolconcentration in the medium The concentration ofstorage lipids, saturated and monounsaturated fattyacids, were enhanced but the EPA content did notchange significantly The EPA content was around 22%of biomass dry weight The maximum EPA yield was335 mg L-1 d-1 and was obtained in aculture containing 01 M glycerol, supplementedperiodically by ammonium chloride This productivitywas 10-fold higher than the EPA productivity obtainedunder mixotrophic conditions

Mixotrophic growth of Phaeodactylum tricornutum on glycerol: growth rate and fatty acid profile

https://www.massey.ac.nz/%7Eychisti/Morphology.pdf

J. M. Fernández Sevilla

Papers

Conversion of CO2 into biomass by microalgae: how realistic a contribution may it be to significant CO2 removal?

Photobioreactors for the production of microalgae

Mixotrophic growth of Phaeodactylum tricornutum on glycerol: growth rate and fatty acid profile

Pellet morphology, culture rheology and lovastatin production in cultures of Aspergillus terreus.

Utilization of the cyanobacteria Anabaena sp. ATCC 33047 in CO2 removal processes.