Tag Archives: Microalgae

Microalgal biofuels: Flexible bioenergies for sustainable development

aaaaaa11111Abstract – To confront energy shortage, global warming and climate changes, biofuels derived from biomass have received increasing attention from the industry, academia and governments. Of the potential sources of biofuels a most promising one is the simple photosynthetic microalgae, which can be grown in open ponds, photobioreactors and fermenters. The advantages to produce biofuels from microalgae include easy adaption to environmental conditions, high photosynthesis efficiency, high lipid content and noncompetition for farmlands. Nonetheless, the real hallmark of microalgae is the fact that these microscopic organisms can provide the biomass feedstock for the flexible production of several different types of renewable and sustainable biofuels such as biodiesel, bioethanol, biogas, biohydrogen among others via thermochemical and biochemical conversion processes. Amazingly, from a sustainability perspective the integrated algal biofuels production, where biodiesel, bioethanol and biogas are continuously produced from one biomass source, can evidently lead to an increase in the energetic productivity of the microalgal biomass, thus improving the economics of this algal biorefinery approach. Developments in several areas, such as genetic and metabolic engineering, are expected to further improve the costeffectiveness of the biofuels from microalgae in an environmentally sustainable manner.
Source: ScienceDirect, December 2, 2013
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Assessment of N2O emission from a photobioreactor treating ammonia-rich swine wastewater digestate

Mezarri et al., October, 2013
Abstract – This study investigated the interactions between naturally occurring bacteria and the microalgae Chlorella vulgaris within a lab scale photobioreactor treating ammonia-rich swine wastewater digestate effluent. Nitrification and denitrification were assessed by targeting ammonia monoxygenases (amoA), nitrate (narG), nitrite (nirS), nitric oxide (norB) and nitrous oxide (nosZ) reductases genes. Oxygen produced from microalgae photosynthesis stimulated nitrification. Under limiting carbon availability (i.e., <1.44 for mg TOC/mg NO2-N and 1.72 for mg TOC/mg NO3–N), incomplete denitrification led to accumulation of NO2 and NO3. Significant N2O emission (up to 118 μg N2O–N) was linked to NO2 metabolism in Chlorella. The addition of acetate as external carbon source recovered heterotrophic denitrification activity suppressing N2O emission. Effluent methane concentrations trapped within photobioreactor was removed concomitantly with ammonia. Overall, closed photobioreactors can be built to effectively remove nitrogen and mitigate simultaneously greenhouse gases emissions that would occur otherwise in open microalgae-based wastewater treatment systems.
Click here to access the article at ScienceDirect
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Biofuels from microalgae—A review of technologies for production, processing, and extractions of biofuels and co-products

4Science Direct (Summary) – 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. Continue reading

Microalgae for biodiesel production and other applications: A review

4Science Direct – (Summary) –  Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO2, wastewater treatment, in human health, as food additive, and for aquaculture…>>Continue reading<<

Source: Science Direct
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Biodiesel – Feedstocks and Processing Technologies

The book “Biodiesel: Feedstocks and Processing Technologies” is intended to provide a professional look on the recent achievements and emerging trends in biodiesel production. It includes 22 chapters, organized in two sections. The first book section: “Feedstocks for Biodiesel Production” covers issues associated with the utilization of cost effective non-edible raw materials and wastes, and the development of biomass feedstock with physical and chemical properties that facilitate it processing to biodiesel. These include Brassicaceae spp., cooking oils, animal fat wastes, oleaginous fungi, and algae. The second book section: “Biodiesel Production Methods” is devoted to the advanced techniques for biodiesel synthesis: supercritical transesterification, microwaves, radio frequency and ultrasound techniques, reactive distillation, and optimized transesterification processes making use of solid catalysts and immobilized enzymes. The adequate and up-to-date information provided in this book should be of interest for research scientist, students, and technologists, involved in biodiesel production.

To read the interested Chapter click on title.
Chapter 1. Non Edible Oils: Raw Materials for Sustainable Biodiesel
Chapter 2. Biodiesel Production from Waste Cooking Oil
Chapter 3. Animal Fat Wastes for Biodiesel Production
Chapter 4. Getting Lipids for Biodiesel Production from Oleaginous Fungi
Chapter 5. Microbial Biodiesel Production – Oil Feedstocks Produced from Microbial Cell Cultivations
Chapter 6. Algal Biomass and Biodiesel Production
Chapter 7. Microalgae as Feedstocks for Biodiesel Production
Chapter 8. Eco-Physiological Barriers and Technological Advances for Biodiesel Production from Microalgae
Chapter 9. Advantages and Challenges of Microalgae as a Source of Oil for Biodiesel
Chapter 10. An Integrated Waste-Free Biomass Utilization System for an Increased Productivity of Biofuel and Bioenergy
Chapter 11. Production of Biodiesel via In-Situ Supercritical Methanol Transesterification
Chapter 12. Transesterification in Supercritical Conditions
Chapter 13. Alternative Methods for Fatty Acid Alkyl-Esters Production: Microwaves, Radio-Frequency and Ultrasound
Chapter 14. Transesterification by Reactive Distillation for Synthesis and Characterization of Biodiesel
Chapter 15. Gas-Liquid Process, Thermodynamic Characteristics (19 Blends), Efficiency & Environmental Impacts, SEM Particulate Matter Analysis and On-Road Bus Trial of a Proven NOx Less Biodiesel
Chapter 16. Biodiesel Production with Solid Catalysts
Chapter 17. Heterogeneous Catalysts Based on H3PW12O40 Heteropolyacid for Free Fatty Acids Esterification
Chapter 18. An Alternative Eco-Friendly Avenue for Castor Oil Biodiesel: Use of Solid Supported Acidic Salt Catalyst
Chapter 19. The Immobilized Lipases in Biodiesel Production
Chapter 20. Progress in Vegetable Oils Enzymatic Transesterification to Biodiesel – Case Study
Chapter 21. Adsorption in Biodiesel Refining – A Review
Edited by Margarita Stoytcheva and Gisela Montero
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