Integrated production of bioethanol and biomethane from rice waste using superior amylolytic recombinant yeast

Ameya Pankaj Gupte; Sara Agostini; Nicoletta Gronchi; Rosemary Anne Cripwell; Marina Basaglia; Marinda Viljoen-Bloom; Willem Heber van Zyl; Sergio Casella; Lorenzo Favaro

doi:10.1016/j.biortech.2024.131947

Integrated production of bioethanol and biomethane from rice waste using superior amylolytic recombinant yeast

Bioresour Technol. 2024 Dec 6:418:131947. doi: 10.1016/j.biortech.2024.131947. Online ahead of print.

Authors

Ameya Pankaj Gupte¹, Sara Agostini², Nicoletta Gronchi³, Rosemary Anne Cripwell⁴, Marina Basaglia⁵, Marinda Viljoen-Bloom⁶, Willem Heber van Zyl⁷, Sergio Casella⁸, Lorenzo Favaro⁹

Affiliations

¹ Waste to Bioproducts-Lab, Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università degli Studi di Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro PD, Italy.
² Waste to Bioproducts-Lab, Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università degli Studi di Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro PD, Italy; BTS Biogas s.r.l., Via Veneto 9, Affi VR, Italy. Electronic address: S.Agostini@bts-biogas.com.
³ Waste to Bioproducts-Lab, Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università degli Studi di Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro PD, Italy. Electronic address: nicoletta.gronchi@unipd.it.
⁴ Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. Electronic address: rosecripwell@sun.ac.za.
⁵ Waste to Bioproducts-Lab, Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università degli Studi di Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro PD, Italy. Electronic address: marina.basaglia@unipd.it.
⁶ Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. Electronic address: mv4@sun.ac.za.
⁷ Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. Electronic address: whvz@sun.ac.za.
⁸ Waste to Bioproducts-Lab, Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università degli Studi di Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro PD, Italy. Electronic address: sergio.casella@unipd.it.
⁹ Waste to Bioproducts-Lab, Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), Università degli Studi di Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro PD, Italy; Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa. Electronic address: lorenzo.favaro@unipd.it.

PMID: 39647711
DOI: 10.1016/j.biortech.2024.131947

Abstract

This study utilized a circular economy approach to convert unripe rice, a low-cost by-product of the rice milling industry, into biofuels using a biorefinery process. The recombinant yeast Saccharomyces cerevisiae ER T12.7 strain was tested for its ability to produce ethanol from unripe rice. In hydrolysis trials with 20 % (dw/v) unripe rice, ER T12.7 showed superior saccharification yields comparable to the commercial enzyme, STARGEN^TM 002. In 1-L bioreactor tests, ER T12.7 produced ethanol as efficiently as the parental ER V1 strain under simultaneous saccharification and fermentation conditions. The spent fermentation broth from both amylolytic strains was evaluated for biomethane production, achieving high yields of up to 373.61 mL CH₄/g volatile solids. This research is the first to demonstrate process integration to produce ethanol and methane from rice waste sequentially, highlighting the potential of unripe rice in biorefining for a circular economy.

Keywords: Bioethanol; Biomethane; Biorefinery; Consolidated bioprocessing; Rice waste streams; Sequential production.