Insight of Pichia kudriavzevii for single cell protein production and fermentation into ethanol using Thai banana as an alternative feedstock

Abstract

Purposes: The objective of this study was to assess the potential of yeast Pichia kudriavzevii (NUNS–4, NUNS–5, NUNS–6, and TISTR5147) and Saccharomyces cerevisiae TISTR5606 strain to utilize banana, Musa ABB cv. (Kluai Namwa) and Musa sapientum L. cv. (Kluai Khai), biomass through the co–production of single cell protein and ethanol. Results: All tested strains grew well on both YPD and banana–based agar, confirming that banana residues can sustain yeast growth. Supplementation with banana biomass significantly enhanced protein and carbohydrate content. Notably, P. kudriavzevii TISTR5147, P. kudriavzevii NUNS–6, and S. cerevisiae TISTR5606 exhibited the highest single cell protein levels (50.85 ± 1.73%, 49.13 ± 1.50%, and 46.96 ± 1.07%, respectively) using Kluai Namwa, compared to controls without banana substrate. Ethanol yields were also increased when banana biomass was included. Co–fermentation of ripe pulp Kluai Khai with YPD resulted in the highest ethanol yields, reaching 77.63 ± 3.11 g/L for P. kudriavzevii NUNS–6, followed by 76.57 ± 4.49 g/L for NUNS–5, 74.17 ± 2.21 g/L for NUNS–4, and 72.32 ± 1.63 g/L for TISTR5147. Therefore, P. kudriavzevii NUNS–6 demonstrated superior efficiency as a dual producer of single–cell protein and ethanol. Conclusion: These findings demonstrate that banana biomass is a cost–effective and sustainable carbon source for single–cell protein and ethanol production. Moreover, the P. kudriavzevii NUNS strains exhibited strong potential for bioconversion of banana residues into high–value products, supporting their applicability in future large–scale biotechnological processes.