Production of poly(3-hydroxybutyrate) by solid-state fermentation with Ralstonia eutropha.

Area of Science:

• Biotechnology
• Microbial Production
• Polymer Science

Background:

• Poly(hydroxyalkanoates) (PHAs) are biodegradable polymers with diverse applications.
• Developing cost-effective production methods for PHAs is crucial for their widespread adoption.
• Agroindustrial residues present a sustainable feedstock for microbial fermentation.

Purpose of the Study:

• To evaluate solid-state fermentation (SSF) as a low-cost technology for PHA production.
• To assess the efficacy of agroindustrial residues (babassu and soy cake) as substrates for Ralstonia eutropha.
• To optimize PHA yield by supplementing the culture medium.

Main Methods:

• Solid-state fermentation using Ralstonia eutropha.
• Cultivation on babassu cake and soy cake as sole carbon sources.
• Supplementation of soy cake medium with sugar cane molasses.
• Quantification of poly(hydroxybutyrate) (PHB) yield and content.

Main Results:

• Maximum PHB yield of 1.2 mg g(-1) medium achieved on soy cake in 36 h.
• PHB yield of 0.7 mg g(-1) medium obtained on babassu cake in 84 h.
• Addition of 2.5% molasses to soy cake increased PHB yield to 4.9 mg g(-1) medium in 60 h, with PHB content reaching 39% (w/w) of dry biomass.

Conclusions:

• Solid-state fermentation is a viable and low-cost technology for PHA production.
• Soy cake, particularly when supplemented with molasses, is a promising substrate for high PHB yield.
• This approach offers a sustainable alternative for the economical production of biodegradable polymers.