Biosaintifika: Journal of Biology & Biology Education
Vol. 18 No. 1 (2026): April 2026

High-Performance Thermotolerant Local Strains for Sustainable Tropical Bioethanol Production via Adaptive Laboratory Evolution

Elza Heryensi (Faculty of Teacher Training and Education, Universitas Bengkulu, Indonesia)
Fitri April Yanti (Faculty of Teacher Training and Education, Universitas Bengkulu, Indonesia)
Rendy Wikrama Wardana (Faculty of Teacher Training and Education, Universitas Bengkulu, Indonesia)
Mochamad Lutfi Firdaus (Faculty of Teacher Training and Education, Universitas Bengkulu, Indonesia)
Noorzana Khamis (Faculty of Educational Sciences and Technology, Universiti Teknologi Malaysia, Malaysia)
Suzieleez Syrene Binti Abdul Rahim (Faculty of Mathematics and Science Education, Universiti Malaya, Malaysia)



Article Info

Publish Date
28 Apr 2026

Abstract

High fermentation temperatures will remain a major limitation to competitive bioethanol production in tropical countries and regions. The objective of the present study was to enrich indigenous microbial strains, improve their performance through Adaptive Laboratory Evolution (ALE), and identify a promising candidate for sustainable bioethanol production. A design an exploratory-comparative laboratory study design was used. Four isolates, Candida tropicalis (CT-BKL01), Kluyveromyces marxianus (KM-BKL02), Bacillus coagulans (BC-BKL03), and Zymobacter palmae (ZP-BKL04), were isolated, characterised, and evolved at elevated temperatures (up to 60 generations). Statistical methods included t-tests (paired and unpaired), fold-change values from proteomics, and nonlinear regression using the Monod-Haldane model. ALE results showed ALE significantly increased the specific growth rate, the activity of the enzyme (p < 0.05), and promoted overexpression of HSP70, GroEL, and ADH-II, whereas its improvement in ethanol titer was observed at 45 °C, with BC-BKL03 as the best strain exhibiting μmax of 0.63 h-¹ that had strong model-appropriate fits (R² ≥ 0.98). From a scientific point of view, this study offers an excellent non-recombinant approach for strain improvement without genetic modification. Operationally, this work contributes to SDGs 7 (Affordable and Clean Energy) and SDGs 13 (Climate Action) by enabling efficient production without active cooling. It enables regional energy sovereignty and reduces carbon emissions, offering a scalable solution for the renewable energy industry in tropical countries.

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Journal Info

Abbrev

biosaintifika

Publisher

Subject

Agriculture, Biological Sciences & Forestry

Description

Biosaintifika: Journal of Biology & Biology Education {PISSN 2085-191X| EISSN 2338-7610} published scientific papers on the results of biology and biology education research {see Focus and Scope}. Editor accepts the article has not been published in other media with the writing format as listed on ...