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Microalgal Growth and Lipid Production from Organic Waste

Lin, Zhongye
http://rave.ohiolink.edu/etdc/view?acc_num=akron1385429109

Abstract Details

2013, Doctor of Philosophy, University of Akron, Chemical Engineering.
Biodiesel becomes an attractive alternative fuel because the reserve of crude oil is diminishing and the need to reduce carbon emission is increasing. The scale of biodiesel production is limited by the inexpensive lipid feedstock available. The aim of this research work is to produce microalgal lipids from organic waste and wastewater as biodiesel feedstock. The process is very environmentally friendly and requires little arable land and only renewable resources. Firstly a new approach that combines wastewater treatment and lipid production was evaluated. The main hypothesis was that bacteria can be easily grown while treating organic wastewater and then fed to phagotrophic algae such as Ochromonas danica for lipid production. Growth and lipid content of O. danica fed with Escherichia coli cells were evaluated in 19 systems under various conditions. It was confirmed that the alga can prey on the bacterium and grow actively with a doubling time as low as 7 h in a wide range of pH and light conditions. The intracellular lipid content of the algal cells reached about 34%. Finding ways to further increase the lipid content is desirable. O. danica was then grown with waste ketchup, which contains high carbohydrate concentrations and is very viscous, making the waste or wastewater treatment difficult. The growth was systematically optimized by evaluating the effects of various culture factors in 20 experimental systems. Under the optimized condition the alga grew with a doubling time of about 10 h and an intracellular lipid content as high as 40%. The maximum cell concentration, limited by the oxygen transfer rate in the bioreactor, reached 30 g/L in 5 days of cultivation. The possibility of further enhancing the algal lipid production by supplementing glycerol and/or acetic acid was next investigated. While carefully controlled addition of acetic acid was crucial, the intracellular lipid content could be raised to a very high level of 80% after 2 days of stimulation. The microalgal lipids were analyzed by thin layer chromatography and triglycerides were found to be the main components. Two major lipid extraction methods were also compared during the study. Overall this research supported the feasibility of using microalgae-based processes to treat waste/wastewater and produce lipids. It offers an effective route to produce biofuel feedstock from various organic wastes. Future studies are desirable on (1) inexpensive O. danica collection methods applicable for large-scale operation, (2) more complete characterization of microalgal lipids, and (3) development of industrial, nutritional and/or pharmaceutical applications of the lipids beyond the biodiesel production.
Lu-Kwang Ju, Dr. (Advisor)
Bi-min Newby, Dr. (Committee Member)
Gang Cheng, Dr. (Committee Member)
Christopher Miller, Dr. (Committee Member)
Donald Ott, Dr. (Committee Member)
164 p.
Chemical Engineering

Recommended Citations

Citations

  • Lin, Z. (2013). Microalgal Growth and Lipid Production from Organic Waste [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1385429109

    APA Style (7th edition)

  • Lin, Zhongye. Microalgal Growth and Lipid Production from Organic Waste . 2013. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1385429109.

    MLA Style (8th edition)

  • Lin, Zhongye. "Microalgal Growth and Lipid Production from Organic Waste ." Doctoral dissertation, University of Akron, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1385429109

    Chicago Manual of Style (17th edition)

akron1385429109
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© 2013, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.