Perspectives on carboxylates generation from Ecuadorian agro-wastes

Area of Science:

• Biotechnology and Bioengineering
• Environmental Science
• Waste Management

Background:

• Agro-waste valorization is crucial for sustainable resource management.
• Fermentation processes can convert organic waste into valuable chemical products.
• Controlling fermentation parameters like pH influences the type and yield of generated compounds.

Purpose of the Study:

• To investigate carboxylate generation from banana, coffee, and cacao agro-waste.
• To compare carboxylate yields under uncontrolled and controlled pH conditions (6.6 and 5.2).
• To identify key factors influencing volatile fatty acid (VFA) and medium-chain fatty acid (MCFA) production.

Main Methods:

• Fermentation of banana, coffee, and cacao agro-waste.
• Application of uncontrolled and controlled pH conditions (6.6 and 5.2).
• Analysis of volatile fatty acids (VFAs) and medium-chain fatty acids (MCFAs) produced.
• Bacterial community analysis at the end of fermentation.

Main Results:

• Acetic acid was the predominant VFA in cocoa waste (96.2 g kg^-1_TVS) at pH 4.5.
• Butyric acid was significant in banana pulp (90.7 g kg^-1_TVS) at controlled pH 6.6.
• Hexanoic and octanoic acids were the main MCFAs, with higher yields observed at pH 6.6.
• Uncontrolled pH fermentation of banana waste produced superior VFAs compared to controlled conditions.
• MCFA yields were notably low at pH 5.2.
• Bacterial communities were dominated by Firmicutes, with Clostridium as a common genus.

Conclusions:

• pH is a critical determinant for the type and recovery of carboxylic acids from agro-waste fermentation.
• Uncontrolled pH fermentation can be advantageous for VFA production, depending on the feedstock.
• Optimizing pH is essential for targeted carboxylate recovery from diverse agro-waste streams.