Current advances in Candida tropicalis: Yeast overview and biotechnological applications.

Candida tropicalis is a nonconventional yeast with medical and industrial significance, belonging to the CTG clade. Recent advancements in whole-genome sequencing and genetic analysis revealed its close relation to other unconventional yeasts of biotechnological importance. C. tropicalis is known for its immense potential in synthesizing various valuable biomolecules such as ethanol, xylitol, biosurfactants, lipids, enzymes, α,ω-dicarboxylic acids, single-cell proteins, and more, making it an attractive target for biotechnological applications. This review provides an update on C. tropicalis biological characteristics and its efficiency in producing a diverse range of biomolecules with industrial significance from various feedstocks. The information presented in this review contributes to a better understanding of C. tropicalis and highlights its potential for biotechnological applications and market viability.

Relation of xylitol formation and lignocellulose degradation in yeast.

One of the critical steps of the biotechnological production of xylitol from lignocellulosic biomass is the deconstruction of the plant cell wall. This step is crucial to the bioprocess once the solubilization of xylose from hemicellulose is allowed, which can be easily converted to xylitol by pentose-assimilating yeasts in a microaerobic environment. However, lignocellulosic toxic compounds formed/released during plant cell wall pretreatment, such as aliphatic acids, furans, and phenolic compounds, inhibit xylitol production during fermentation, reducing the fermentative performance of yeasts and impairing the bioprocess productivity. Although the toxicity of lignocellulosic inhibitors is one of the biggest bottlenecks of the biotechnological production of xylitol, most of the studies focus on how much xylitol production is inhibited but not how and where cells are affected. Understanding this mechanism is important in order to develop strategies to overcome lignocellulosic inhibitor toxicity. In this mini-review, we addressed how these inhibitors affect both yeast physiology and metabolism and consequently xylose-to-xylitol bioconversion. In addition, this work also addresses about cellular adaptation, one of the most relevant strategies to overcome lignocellulosic inhibitors toxicity, once it allows the development of robust and tolerant strains, contributing to the improvement of the microbial performance against hemicellulosic hydrolysates toxicity. KEY POINTS: • Impact of lignocellulosic inhibitors on the xylitol production by yeasts • Physiological and metabolic alterations provoked by lignocellulosic inhibitors • Cell adaptation as an efficient strategy to improve yeast's robustness.