Microalgae for biodiesel
Development of a novel, economically viable bio-process integrating production of microalgae-for-biodiesel with wastewater treatment
Tech Area / Field
- NNE-FUE/Fuels/Non-Nuclear Energy
- NNE-SOL/Solar Energy/Non-Nuclear Energy
3 Approved without Funding
Tbilisi State University, Georgia, Tbilisi
- National Renewable Energy Laboratory, USA, CO, Golden\nClean Energy Centre, Graduate School of Medicine and Engineering, University of Yamanashi, Japan, Kofu\nEnergy Department (DENERG) Politecnico di Torino, Italy, Torino
Project summaryThe Project aim: In recent years, oil crops based biodiesel (referred to as first generation biodiesel) production has attained industrial levels but its impact towards meeting the overall diesel fuel demands is expected to remain limited due to competition with food and fiber production for the use of arable land and high water and fertilizers requirements. In this regard algae/microalgae, which can be cultivated using marine water and/or wastewater and yield more energy per unit area than terrestrial plants are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first generation biodiesel.
The overall goal of the project is the development of economically viable bio-process technology integrating production of oil rich microalgae, fertilizers and/or feed with wastewater treatment. Project is focused on the use of heterotrophic microalgae, which are now considered promising low-cost feedstock as their oils are similar by composition to that of vegetable oils, the culture of these microalgae species can be cultivated in bioreactors in the absence of light and is affected neither by seasons nor by climate and can accumulate high amount of lipids within a short period of time as well as grow well on a variety of substrates including inexpensive and locally available sources of nutrients like wastewater from food industry, anaerobic digestion systems etc. Project aims to cover all stages of microalgae-for-biodiesel production including isolation, identification and screening of microalgae strains able to accumulate high amount of lipids in heterotrophic growth; study of optimal cultivation conditions and culture management for sustainable high biomass and oil yields; design, construction and testing of lab-scale system that will be best suited to the selected strains and culture media. Microalgae cake residual after oil extraction will be studied for application as fertilizer and/or feed. Finally, ecological, energetic and economical parameters of the integrated bio-process will be assessed.
Current status: Considering that most species of algae/microalgae are obligate phototrophs with simple growing requirements (light, CO2, water, N and P), algae/microalgae -for-biodiesel production in naturally or artificially illuminated environments like open ponds and/or photobioreactors was prevailing over the past decades. In spite of relatively low construction and operating costs, efficiency of open pond systems for algae biomass commercial production proved to be limited because of poor light diffusion inside the pond decreasing with depth; constant contamination of monoculture by fungi, bacteria and protozoa; poor utilization of CO2 due to evaporation or stripping, dependence of environmental growth parameters of cultivation primarily on local weather conditions; increasing costs for land use etc. Similar to the open-pond concept, large-scale photobioreactors (PBR) that are protected from direct fallout, relatively safe from invading microorganisms, where temperatures are controlled with an enhanced CO2 fixation, have some disadvantages that make their use uneconomical for microalgae-for-biodiesel production. In particular, at operational volumes of 50-100 l or higher it is no longer possible to disperse light efficiently and evenly inside the PBR; developed microalgal biofilm fouls PBR surfaces and thereby limits light penetration into the culture; PBR needs high initial investment in infrastructure and increased costs for maintenance. Referring to recent publications, microalgae capable of accumulating lipids in heterotrophic growth are considered promising for microalgae low-cost production at any scale. Such optimism is conditioned by results obtained under the laboratory studies. For example: under some heterotrophic conditions, the growth rate, lipid content and microalgal biomass yields and cell density are significantly higher compared to autotrophic cultures and are mainly dependant on the species and strains used. Moreover, in general heterotrophic growth overcomes major limitations of producing useful products from microalgae: dependency on light which significantly complicates the process and increases costs; in most cases heterotrophic cultivation is far cheaper, simpler to construct facilities, and easier than autotrophic cultivation to maintain on a large scale; heterotrophic cultivation may allow large volume applications such as wastewater treatment combined, or separated, with production of biofuels.
As heterotrophic production of microalgae-for-biodiesel is a relatively new field of research, the main biological challenges include screening and bringing into industrial culture of species with ‘optimal’ attributes such as high growth rate, high biomass and oils yields and tolerance to growth inhibitors.
The participants’ expertise: Project builds on the extensive research and management experience of project participants in biofuels (biogas, bio-hydrogen, bioethanol) production; algae cultivation, chemical engineering and mechanical processing technologies. Since 1997 up to now, project team members participated in 11 international R&D projects. In recent years they have published more than 30 research papers in local and international journals.
Meeting the ISTC goals and objectives: Project fully meets the ISTC goals since it is exceptionally peaceful. 9 Scientists who previously dealt with the development of weapons of mass destruction will participate in the implementation of the project. Two young researchers also will be involved in the project. Adherence to these objectives can be attained by planned wide involvement of scientists and participating institution into international scientific community.
Scope of activities: Project implementation will cover the following studies: (i)Collecting, characterization and screening of oil rich heterotrophic microalgae strains endemic in 12 soil-climatic zones of Georgia; (ii) Development of optimum process conditions for sustainable high microalgae biomass and oil yields; (iii) Development of optimum cultivation system and design, construction and testing of lab scale system best suited for microalgae biomass production using wastewater from dairy, brewery and liquid fraction of effluent from anaerobic digester treating cattle manure as substrate for growth; (iv) Study of microalgae cake residual after oil extraction for use as commercial organic-mineral fertilizer and/or feed; (v) Assessment of ecological, energetic and economic parameters of the bio-process integrating production of microalgae-for-biodiesel, feed and/or fertilizers with wastewater treatment.
Technical approach and methodology: Project will be carried out at the TSU microbiological, analytical chemistry and biotechnological rooms using analytical and measuring technique, instruments and tools existing at the labs. Taking into account that a number of species in the genera Chlorella, Chlamydomonas and Scenedesmus are known to accumulate high amount of lipids in heterotrophic growth when utilizing organic substrates like some carbohydrates and VFA, isolation of above microalgae species will be the main focus of the task 1. Isolation, enrichment and obtaining axenic cultures of microalgae strains will be done according to methods given in “Algal culturing techniques” by Robert Arthur Andersen (2005) Elsevier Inc. To select fast growing microalgae strains capable of accumulating high amount of lipids in heterotrophic growth, in series of experiments growth rate, titer and yields of microalgae biomass and oil will be studied as a function of pH, temperature, concentration of organic carbon sources like glucose, fructose, lactose, acetate, formate and butyrate and mineral nutrients – N and P. To develop optimum cultivation system, investigations will be focused both on the suspended and attached cultivation modes. Different materials will be tested as surface for microalgae attachment including polystyrene, polyethylene and polyurethane foam. Performance of attached and suspended microalgal culturing system will be compared in terms of culturing time and total biomass and oil yields. To make recommendations for use microalgae cake as feed and /or fertilizer, microalgae cake will be studied for chemical composition. Assessment of ecological, economic and energetic effectiveness of bio-process integrating microalgae-for-biodiesel production with wastewater treatment will be done according to removal of organic carbon and mineral compounds from wastewater and calculation of mass and energy balance of the overall bio-process. For estimation economic efficiency will be used commercial software available.
Role of Foreign Collaborators: Dr. Maria Ghirardi (NREL, USA), Prof. Massimo Santarelli (Italy), and Professor Masaharu Komiyama (CERC, Yamanashi University) expressed their interest to become Collaborators of the Project. Dr. Maria Ghirardi will participate in the development of growth conditions for high yield of selected heterotrophic microalgae biomass and oil, Prof. Massimo Santarelli will assist in the screening of oil rich microalgae strains and estimation of energy efficiency of the overall process. Professor Masaharu Komiyama will participate in the development of optimum cultivation system including design of bioreactor for production of selected microalgae biomass.
Expected results and their application: Expected specific results that will provide achievement of the basic objective of the project are as follows: (i) unique collections of oil rich microalgae strains endemic in 12 soil-climatic zones of Georgia; (ii) strains of industrially relevant, robust oil rich microalgae able to grow heterotrophically; (iii) optimum process conditions and cultivation system for maximal microalgal biomass and oil yield when treating wastewater from brewery and dairy and liquid fraction of the effluent from anaerobic digester; (iv) recommendations for optimal use of microalgae cake residual after oil extraction. In whole, project will result in the economically viable bio-process technology integrating microalgae-for-biodiesel and fertilizers and/or feed production with treatment of wastewaters. Considering that wastewater from about 300 small and medium scale breweries and dairies and 1200 biogas reactors, which operate presently at rural Georgia, don’t undergo any treatment and cause water and soil pollution, project results will be used to involve both governmental agencies and business groups and inpiduals who are reasonably interested in getting our academic know-how taken up and taken forward for using on an industrial or a general business scale.
The project’ influence on progress in this area: Proposed project has national and international significance as well. Despite the extremely wide biopersity in Georgia where saline and freshwater lakes are located in different soil-climatic zones, microalgae in general had never been studied and are effectively unknown. Therefore, creation of unique collections of oils accumulating microalgae proposed here is the first attempt to characterize the genetic persity and metabolic potential of microalgae from this part of the World. New strains of industrially relevant, robust microalgae able to accumulate high amount of lipids in heterotrophic growth using wastewater from food industry and liquid effluent from anaerobic digester as substrate for growth can efficiently fit both in the addressing cost problems related to microalgae based biodiesel production and wastewater treatment.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.