Harvesting the Microalga Chlorella sorokiniana by Fungal-Assisted Pelletization

Journal Article · Sat Dec 01 00:00:00 EST 2018 · Journal of Biobased Materials and Bioenergy

DOI:https://doi.org/10.1166/jbmb.2018.1798· OSTI ID:1581802

Toscano, Lydia ^[1]; Ogden, Kimberly L. ^[2]; Ogden, Greg ^[2]; Cervantes, Lourdes ^[2]; Steichen, Seth A. ^[2]; Brown, Caitlin ^[3]; Samaniego, Blancka Y. ^[2]; Brown, Judith K. ^[4]

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1. Technological Inst. of Mexicali (Mexico); University of Arizona
2. Univ. of Arizona, Tucson, AZ (United States)
3. Autonomous Univ. of Baja California (Mexico)
4. Technological Inst. of Conkal (Mexico)

Currently, the co-cultivation of fungal and microalgal cells is considered a potential technology to minimize the harvesting cost and energy inputs in the algae-to-biofuel approach. In the present study, the co-cultivation of five selected filamentous fungi and microalgae Chlorella sorokiniana to form cell pellets was evaluated under different conditions, such as organic carbon (glucose, fructose, sucrose, and maltose) and nitrogen (urea, peptone, yeast extract, and sodium nitrate) source content with and without the presence of an alternative carbon source (wheat straw), and initial fungal/microalgae cells ratio for mixotrophic growing. In addition, cellulase activity and zeta potential measurements were carried out to obtain a better understanding of the pelletization process. Aspergillus flavus was found most efficient for pelletizing in the nutrient supplemented spent BG-11 in spite of its alkaline pH (7.5–8.3) under mixotrophic growing, being able to harvest up to 96% of the microalgal cells (4.2 x 10⁷ cells mL^-1 initial algal concentration) within 48 h at supplementation of 5, 10, and 1 g L^-1 of fructose, NaNO₃, and KH₂PO₄, respectively. The harvesting efficiency in terms of optical density at 750 nm as well as the variation of residual sugars, pH, and cellulase enzyme activity (2.3 U mL^-1 maximum value) with time was also studied. A. flavus strain investigated in this work could emerge as an efficient and economically viable method in microalgae harvesting for biofuel production as well as in the production of other valuable compounds from extracellular fungal metabolites.

• Research Organization: Univ. of Arizona, Tucson, AZ (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B)
• Grant/Contract Number: EE0006269
• OSTI ID: 1581802
• Journal Information: Journal of Biobased Materials and Bioenergy, Journal Name: Journal of Biobased Materials and Bioenergy Journal Issue: 6 Vol. 12; ISSN 1556-6560
• Publisher: American Scientific Publishers
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
co-culture
filamentous fungi
microalgae harvest
pelletization