Bioconversion Pathways for Bioethanol Production from Food Waste

Bioconversion of food waste into bioethanol encompasses a series of integrated steps designed to transform complex organic residues into fermentable sugars and ultimately into ethanol. The process typically begins with pretreatment—mechanical, thermal or chemical—to disrupt the lignocellulosic matrix and render carbohydrates more accessible. This is followed by hydrolysis, often enzymatic, which cleaves polysaccharides into monosaccharides. Subsequent fermentation employs specialised microorganisms such as Saccharomyces cerevisiae, Pichia species or filamentous fungi to convert these sugars into ethanol. Two principal process configurations prevail: separate hydrolysis and fermentation (SHF), wherein hydrolysis and fermentation occur in discrete vessels, and simultaneous saccharification and fermentation (SSF), which combines both in a single reactor to reduce inhibition and improve yields. Advances in enzyme formulation, microbial strain engineering and process integration have driven yields towards theoretical maxima, while co‐production strategies—such as coupling bioethanol with biomethane generation from residual solids—offer routes to enhanced energy recovery. This biorefinery approach not only mitigates the environmental footprint of food waste disposal but also contributes to a circular bioeconomy by supplying renewable transport fuels and value‐added co‐products. Life cycle assessment and techno‐economic evaluations are critical for identifying bottlenecks and guiding scale‐up of promising pathways.

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Bioconversion Pathways for Bioethanol Production from Food Waste publication trend

The graph below shows the total number of articles in bioconversion pathways for bioethanol production from food waste across all publications each year (not limited to Nature Index journals).

Technical terms

Pretreatment: Processes (physical, chemical or thermal) applied to food waste to disrupt cell walls and expose carbohydrates for hydrolysis.

Enzymatic hydrolysis: Use of cellulases, hemicellulases or amylases to break down polysaccharides into fermentable sugars.

Separate hydrolysis and fermentation (SHF): A bioconversion strategy in which enzymatic saccharification and microbial fermentation are conducted in separate reactors.

Simultaneous saccharification and fermentation (SSF): A combined process where hydrolysis and fermentation occur concurrently in one vessel, reducing product inhibition and process time.

Anaerobic digestion: Microbial degradation of organic residues in the absence of oxygen, producing biogas (methane and carbon dioxide).

References

1. Sustainability of food waste biorefinery: A review on valorisation pathways, techno-economic constraints, and environmental assessment. Bioresource Technology (2020).
2. Enhanced Energy Recovery from Food Waste by Co-Production of Bioethanol and Biomethane Process. Fermentation (2021).
3. Valorisation of source-separated food waste to bioethanol: pilot-scale demonstration. Biomass Conversion and Biorefinery (2022).