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One-step polyhydroxybutyrate production from potato starch by engineered Bacillus subtilis
Maryia Shahayeva1, Jordi Ferrando1, Javier Navarro1
1Faculty of Pharmacy and Food Science Technology, Department of Biology, Healthcare and the Environment, Microbiology Section, Universitat de Barcelona, Avinguda av. Joan XXIII, 27-31, Barcelona 08028, Spain.
Bioresource Technology
|May 21, 2026
Summary
Bacillus subtilis was engineered for high-level polyhydroxybutyrate (PHB) production, achieving over 50% dry cell weight. This breakthrough enables efficient bioplastic manufacturing from sustainable starch sources.
Area of Science:
- Microbiology
- Biotechnology
- Polymer Science
Background:
- Bacillus subtilis is a well-established industrial microorganism.
- Previous polyhydroxybutyrate (PHB) production in B. subtilis was limited to below 13% of dry cell weight (DCW).
Purpose of the Study:
- To engineer Bacillus subtilis for enhanced polyhydroxybutyrate (PHB) biosynthesis.
- To explore PHB production from diverse carbon sources, including unprocessed starch.
Main Methods:
- Genetic engineering of B. subtilis for PHB pathway optimization and phasin expression.
- Utilizing α-amylase (amyQ) for direct PHB accumulation from potato starch.
- Characterization of the produced PHB polymer.
Main Results:
- Achieved PHB accumulation of 47.3-54.9% DCW from various carbon sources.
- Demonstrated direct, one-step PHB production from potato starch reaching 51.8% DCW.
- Produced PHB with characteristics comparable to commercial standards.
Conclusions:
- Engineered B. subtilis is a viable Gram-positive platform for efficient and sustainable PHB production.
- Direct utilization of unprocessed starch offers a cost-effective route for bioplastic manufacturing.
- This study significantly advances the potential of B. subtilis in industrial biopolymer synthesis.
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