Date of Submission

5-2025

Document Type

Thesis

Degree Name

Master of Science in Chemical Engineering

Department

Chemistry and Chemical Engineering

Advisor

Kristine Horvat, Ph.D.

Committee Member

Pier Cirillo, Ph.D.

Committee Member

Shayok Mukhopadhyay, Ph.D.

Keywords

Bioethanol, Seaweed, Enzymatic Hydrolysis, Fermentation, Separate Hydrolysis and Fermentation (SHF), Simultaneous Saccharification and Fermentation (SSF)

LCSH

Algal biofuels, Marine algae, Fermentation, Algal Enzymes, Hydrolysis

Abstract

The increasing global energy demand, depletion of fossil fuel reserves, and environmental concerns have driven the search for sustainable biofuel alternatives. Seaweeds (macroalgae) are promising feedstocks for bioethanol production due to their high carbohydrate content, rapid growth rates, lack of lignin, and non-competition with arable land. This study investigates the bioethanol production potential of three seaweed species, Codium fragile, Monostroma grevillei, and Fucus distichus, using enzymatic hydrolysis and fermentation via Separate Hydrolysis and Fermentation (SHF) and Simultaneous Saccharification and Fermentation (SSF) processes. Hydrolysis was catalyzed using either α-Amylase or Celluclast 1.5L, and Saccharomyces cerevisiae was employed for fermentation. Out of 12 experimental runs, 9 yielded quantifiable bioethanol. The highest ethanol concentration (11.3 wt.%) was obtained from C. fragile using SHF, while the lowest (3.5 wt.%) was observed in the same species under SSF conditions. The higher SHF yield is attributed to the ability to optimize hydrolysis and fermentation independently, enabling full enzymatic activity at elevated temperatures (45–50􀯗°C), which is particularly effective for depolymerizing the ulvan-rich polysaccharides in C. fragile. In contrast, SSF required a temperature compromise, reducing hydrolytic efficiency. Distillate volumes ranged from 8.0 to 108.5 mL, with SHF generally outperforming SSF. Characterization via IR and 1H-NMR spectroscopy confirmed the presence of ethanol in all successful trials, alongside trace impurities in select experiments. These results demonstrate the viability of seaweeds as a renewable source of bioethanol and highlight how process configuration and enzyme selection significantly influence yield and purity. Further optimization is recommended to maximize output and validate these findings against existing literature benchmarks.

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