. 2021 Dec 8;12:744437. doi: 10.3389/fmicb.2021.744437

TABLE 3.

Antimicrobial activity of wet (WB), dried at low temperature (DB), and lyophilized (LB) Spirulina biomasses.

	Penicillium roqueforti			Escherichia coli
	10%	20%	30%
Wet biomass
WB	0.0 ± 0.0^f	12.9 ± 0.41^e	13.2 ± 0.47^e	+
WB_A	13.4 ± 0.51^d	12.8 ± 0.44^e	13.1 ± 0.44^e	++
WB_F	13.5 ± 0.50^d	13.0 ± 0.52^e	13.3 ± 0.51^e	+++
WB_AF	13.5 ± 0.44^d	13.1 ± 0.49^e	30.4 ± 1.01^c	+++
Dried biomass
DB	4.3 ± 0.17^e	13.0 ± 0.43^e	21.7 ± 0.86^d	−
DB_A	26.1 ± 1.02^c	21.7 ± 0.91^d	21.6 ± 0.88^d	±
DB_F	13.0 ± 0.49^d	13.2 ± 0.43^e	13.2 ± 0.54^e	+
DB_AF	13.6 ± 0.46^d	13.4 ± 0.41^e	13.1 ± 0.53^e	±
Lyophilized biomass
LB	13.1 ± 0.51^d	26.2 ± 0.84^c	8.7 ± 0.23^f	±
LB_A	34.8 ± 1.32^b	34.8 ± 1.36^b	100.0 ± 2.29^a	+
LB_F	34.7 ± 1.36^b	21.9 ± 0.78^d	34.8 ± 1.09^c	+++
LB_AF	43.5 ± 1.71^a	47.8 ± 1.03^a	56.5 ± 1.18^b	+++

Data are the means of three independent analyses. ^a–fValues in the same column with different superscript letters differ significantly (P < 0.05). All biomasses were also treated with Alcalase^® (A, 1% vol/wt), fermented with Lactiplantibacillus plantarum T0A10 (F, final cell density of circa 7 log10 cfu/g), or fermented and treated with Alcalase^® (AF). Enzymatic and microbial treatments were carried out at 30°C for 24 h. Antifungal activity was determined by hyphal radial growth inhibition of Penicillium roqueforti DPPMAF1 after 6 days of incubation at 25°C in PDA containing 30% vol/vol of the extract. Inhibitory activity against gastrointestinal pathogen Escherichia coli was scored as follows: −, no inhibition; ±, inhibition halo of 1–2 mm; +, inhibition halo of 3–4 mm; ++, inhibition halo of 5–6 mm; +++, inhibition halo of 7–9 mm.