Influence of Nitrogen and Carbon Sources on Riboflavin Production by Wild Strain of Candida sp

Kinetics of Riboflavin Production by Hyphopichia wangnamkhiaoensis under Varying Nutritional Conditions

Riboflavin, an essential vitamin for humans, is extensively used in various industries, with its global demand being met through fermentative processes. Hyphopichia wangnamkhiaoensis is a novel dimorphic yeast species capable of producing riboflavin. However, the nutritional factors affecting riboflavin production in this yeast species remain unknown. Therefore, we conducted a kinetic study on the effects of various nutritional factors-carbon and energy sources, nitrogen sources, vitamins, and amino acids-on batch riboflavin production by H. wangnamkhiaoensis. Batch experiments were performed in a bubble column bioreactor to evaluate cell growth, substrate consumption, and riboflavin production. The highest riboflavin production was obtained when the yeast growth medium was supplemented with glucose, ammonium sulfate, biotin, and glycine. Using these chemical components, along with the mineral salts from Castañeda-Agullo's culture medium, we formulated a novel, low-cost, and effective culture medium (the RGE medium) for riboflavin production by H. wangnamkhiaoensis. This medium resulted in the highest levels of riboflavin production and volumetric productivity, reaching 16.68 mg/L and 0.713 mg/L·h, respectively, within 21 h of incubation. These findings suggest that H. wangnamkhiaoensis, with its shorter incubation time, could improve the efficiency and cost-effectiveness of industrial riboflavin production, paving the way for more sustainable production methods.

A computer vision chemometric-assisted approach to access pH and glucose influence on susceptibility of Candida pathogenic strains

Microorganisms adapt to environmental conditions as a survival strategy for different interactions with the environment. The adaptive capacity of fungi allows them to cause disease at various sites of infection in humans. In this study, we propose digital images as responses of a complete factorial 2³. Furthermore, we compared two experimental approaches: the experimental design (3D) and the checkerboard assay (2D) to know the influence of pH, glucose, and fluconazole concentration on different strains of the genus Candida. The digital images obtained from the factorial 2³ were used as input in the PCA-ANOVA to analyze the results of this experimental design. pH modification in the culture medium modifies the susceptibility in some species less adapted to this type of modification. For the first time, to the best of our knowledge, digital images were used as input to PCA-ANOVA to obtain information on Candida spp.. Therefore, a higher concentration of antifungals is needed to inhibit the same strain at a lower pH. In short, we present an alternative with less use of reagents and time. In addition, the use of digital images allows obtaining information about fungal susceptibility with three or more factors.