The effects of environmental stressors on biofilm formation of Chlorella vulgaris

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Carra Parker (Creator)
Appalachian State University (ASU )
Web Site:
Mark Venable

Abstract: Biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Recently, environmental stressors have been implicated in the induction of biofilm formation; however, it is unclear whether all stressors, or a select few, are responsible for this phenomenon. This study aimed to investigate the effects of three stressors on biofilm formation of Chlorella vulgaris. We hypothesized that C. vulgaris would experience stress in response to nitrogen depletion (glyoxylate treatment), reduced or elongated day lengths, and with increased culture turbulence. Additionally, we hypothesized that common indicators of stress, such as growth inhibition, cell size changes, and production of reactive oxygen species, would correlate with biofilm formation. A turbulence level of 300-rpm decreased growth while increasing superoxide production and flocculation efficiency. Although a significant increase in EPS secretion was measured in both short and long day lengths, stress responses to day length changes were not observed. Nitrogen depletion induced low-level superoxide production for the highest glyoxylate concentrations. Collectively, the results indicate that stress response varies according to the applied stress, biofilm formation is not linked to a particular stress indicator, and that C. vulgaris uses cell stickiness both as a mechanism for substrate adherence and cellular aggregation.

Additional Information

Parker, C. (2013). The effects of environmental stressors on biofilm formation of Chlorella vulgaris. Unpublished master's thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2013
Microalgae, stressor, biofilm, exopolymeric substances (EPS), aggregates

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