L 1 tryptone

Test microorganisms including bacteria Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis, fungus Aspergillus niger and yeast Candida utilis were cultivated in standard LB growth medium (10 g L⁻¹ tryptone (Sigma Aldrich; St. Louis, MO, USA), 5 g L⁻¹ yeast extract (Sigma Aldrich; St. Louis, MO, USA), 5 g L⁻¹ sodium chloride (Nin Saltwork; Nin, Croatia), 20 g L⁻¹ agar (Sigma Aldrich; St. Louis, MO, USA)). One hundred microliters of overnight culture were spread on solid LB agar in Petri dishes. Fifty microliters of microalgae extract were applied on a sterile disk and placed on the surface of a solid LB medium with a test microorganism. Neomycin and nystatin at 50 mg mL⁻¹ were used as a positive control, while 100% methanol was used as a negative control. Plates with bacterial and fungal strains were incubated at 30 °C for 24 and 48 h, respectively. Afterwards, inhibition zones around the disk were measured. For all test microorganisms, assays were done in duplicate.

S. cerevisiae H1022 (ATCC cat. 32167), a Crabtree-positive yeast, was selected as the second microbial representative to monitor the metabolic switch between glucose uptake and ethanol formation to ethanol consumption online. For these cultivations, the peptone, dextrose, yeast extract (YPD) complex medium was used [84 ], composed of 10 g L⁻¹ yeast extract (cat. Y1625, Sigma-Aldrich), 20 g L⁻¹ tryptone (cat. 70173, Sigma-Aldrich) and 20 g L⁻¹ glucose (cat. G2870, Sigma-Aldrich), which were autoclaved together.
Temperature was set to 37 °C, shaking frequency to 180 rpm, and shaking amplitude to 50 mm. Biomass was determined identically to the E. coli experiments. For metabolite analytics, ethanol was measured instead of ammonia.