University of Illinois Urbana-Champaign

Bicarbonate trigger in mixed culture of algae increases carbohydrate content of biomass

Avila, Nick

Content Files
AVILA-THESIS-2021.pdf

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https://hdl.handle.net/2142/113926

Description

Title
Bicarbonate trigger in mixed culture of algae increases carbohydrate content of biomass
Author(s)
Avila, Nick
Issue Date
2021-12-09
Director of Research (if dissertation) or Advisor (if thesis)
Guest, Jeremy S
Department of Study
Civil & Environmental Eng
Discipline
Environ Engr in Civil Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2022-04-29T21:35:52Z
Keyword(s)
  • microalgae
  • wastewater
  • biofuels
  • carbohydrates
  • lipids
Abstract
Residual nitrogen and phosphorus from wastewater treatment plant effluents remains a key challenge as governments work to reduce the incidence of harmful algal blooms in surface waters. Permits for nitrogen and phosphorus release from municipal wastewater treatment plants are becoming increasingly common and strict in many areas of the US. Algal-based wastewater treatment technologies are uniquely situated to recover these nutrients to lower than current limits of technology and potentially produce valuable byproducts such as biofuels. A key barrier to financial viability is the sale of the biomass, the value of which could be increased by enriching the biomass in lipid and carbohydrates. Previous research has shown that adding sodium bicarbonate just before nutrient depletion can drastically increase the lipid content of algal biomass, but this has only been shown in pure cultures. The goal of this study is to test the effectiveness of a bicarbonate trigger for lipid and carbohydrate accumulation on a mixed culture of algae via lab-scale batch experimentation. This study found a 67.8% increase in volatile suspended solids concentration for the 50 mM bicarbonate addition condition versus a 18.6% increase for the 0 mM bicarbonate addition (control) condition. This increase was found to be mostly from carbohydrate accumulation with an increase in the carbohydrate to protein ratio of 3.1 fold and 9.6 fold for the 0 mM and 50 mM bicarbonate conditions, respectively. This increase in carbohydrates, rather than lipids is a unique result and is likely due the fact that a mixed community of algae was used with a low solids retention time. This could increase the revenue from both an increased mass of produced biomass due to the higher solids concentration and an increased value of the final product due to increased carbohydrate content. This increased biomass value could potentially offset some of the costs of algal-based wastewater treatment, making it more financially viable.
Graduation Semester
2021-12
Type of Resource
Thesis
Permalink
http://hdl.handle.net/2142/113926
Copyright and License Information
Copyright 2021 Nickolas Avila

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Graduate Theses and Dissertations at Illinois