Poly(3-hydroxybutyrate) production using supplemented corn-processing byproducts through Cupriavidus necator via solid-state fermentation: Cultivation on flask and bioreactor scale

Mohammad Sadegh Jafari ¹, Parisa Hejazi ¹

⁰Biotechnology Research Laboratory, School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran.

Journal of Biotechnology +

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June 19, 2024

View abstract on PubMed

Summary

This study explored using food waste like corn germ and bran to produce Poly(3-hydroxybutyrate) (PHB). Optimized fermentation with cheese whey and molasses significantly boosted PHB yield, making bioplastics more cost-effective.

Area Of Science

Biotechnology
Materials Science
Sustainable Chemistry

Background

Poly(3-hydroxybutyrate) (PHB) is a biodegradable polymer with potential as a sustainable alternative to conventional plastics.
High production costs currently limit the widespread adoption of PHB.
Utilizing low-cost, abundant raw materials is crucial for improving the economic viability of PHB production.

Purpose Of The Study

To investigate the use of food processing byproducts as low-cost substrates for PHB production.
To optimize solid-state fermentation conditions for enhanced PHB yield.
To evaluate PHB production efficiency at both flask and bioreactor scales.

Main Methods

Solid-state fermentation using corn germ and corn bran as substrates.
Supplementation with molasses and cheese whey to enhance nutrient availability.
Optimization of fermentation parameters including substrate composition, temperature, moisture, and nutrient addition using the One Factor at a Time technique.
Scale-up studies in a packed-bed bioreactor to assess the impact of aeration.

Main Results

The optimal substrate composition for flask-scale PHB production was a 1:1 mass ratio of corn germ to corn bran, supplemented with 20% (v/w) cheese whey, achieving a yield of 4.1 g/kg Initial Dry Weight Substrate (IDWS) after 72 hours.
Bioreactor-scale experiments demonstrated a significant increase in PHB yield, reaching a maximum of 8.4 g/kg IDWS after 72 hours, representing over a 100% improvement.
Optimal aeration rate in the bioreactor was determined to be 0.5 L/(kg IDWS·h).

Conclusions

Food processing byproducts can be effectively utilized as low-cost substrates for PHB production via solid-state fermentation.
Optimization of substrate composition and fermentation conditions, including aeration, significantly enhances PHB yield.
The findings suggest a viable pathway for reducing the production cost of PHB, promoting its wider application as a sustainable bioplastic.

Keywords:

Biopolymer Cheese whey Corn byproduct Food processing residues Molasses Solid state fermentation