Influence of sweet whey permeate utilization on <scp> <i>Tetradesmus obliquus</i> </scp> growth and β‐galactosidase production
Jihed Bentahar, Jean‐Sébastien Deschênes
Abstract
Abstract The practicability of culturing microalgae in mixotrophic mode using sweet whey permeate (SWP), a highly perishable by‐product stream from cheese manufacturing, is evaluated for microalgal growth and β‐galactosidase production. This study is conducted with Tetradesmus obliquus , species known for their ability to adapt to various conditions with different carbon sources. The influence of pure lactose, the primary carbon source of SWP, is first surveyed. Partial substitutions of the basal culture medium with SWP in various proportions are then conducted. Results show that substituting 60% (v/v) of the culture medium with SWP significantly enhances T. obliquus growth (up to 2.1 g L −1 ) and total enzyme production (up to 208.5 U L −1 ). Besides, a molecule expected to be a galactooligosaccharide (GOS) is detected in the presence of high SWP proportions. Overall results suggest a short‐term culture duration (around 8 days) for producing the β‐galactosidase enzyme and a long‐term culture duration (over 15 days) for biomass production. However, the use of 100% (v/v) SWP seems to be non‐profitable due to a lack of some essential nutrients.