Enhanced Phytase Production by Chlorella minutissima under Controlled CO₂, Light, and Substrate Conditions”

• DOI: https://doi.org/10.22533/at.ed.1813622607051

• Palavras-chave: ...

• Keywords: phytic acid, enzyme, mixotrophic, microalgae

• Abstract: Phytase is a key enzyme in the food and feed industries due to its ability to enhance phosphorus bioavailability and improve nutritional value. Industrial production of phytase is traditionally achieved through microbial fermentation using bacteria, yeasts, or filamentous fungi. In this study, an alternative approach for phytase production is proposed using the microalga Chlorella minutissima LEM 15 cultivated under mixotrophic conditions. The microalga was grown in Modified Bristol’s Medium (MBM), in which inorganic phosphate was replaced by phytic acid as the sole carbon and phosphorus source. Cultivations were conducted at 25 ± 1°C under a 12 h photoperiod for 14 days. The effects of phytic acid concentration, light intensity (0–115 µmol m⁻² s⁻¹), and culture conditions, including agitation and aeration, were evaluated. Maximum phytase activity (671.2 ± 25.5 U L⁻¹) was obtained using 0.5% (w/v) phytic acid, 10% (v/v) inoculum, light intensity of 58 µmol m⁻² s⁻¹, and forced aeration at 0.5 vvm, with a biomass increase of 5.5 × 10⁶ cells mL⁻¹. Bioprocess parameters under optimal conditions were determined as follows: μ max = 0.029 h⁻¹, td = 23.78 h, Y X/S = 0.032 g g⁻¹, Y P/S = 53.8 U g⁻¹, and Y P/X = 1664.4 U g⁻¹. Additionally, wheat bran extract was identified as a promising alternative substrate, yielding phytase activity of 677 U L⁻¹ within four days of cultivation. In contrast, the use of citrus pulp extract negatively affected phytase production, likely due to increased medium turbidity limiting light penetration and photosynthetic performance. These findings demonstrate the potential of mixotrophic microalgal systems as a novel and sustainable platform for phytase production, with promising applications in the development of value-added bioprocesses.