TY - JOUR
T1 - Adaptive laboratory evolution to hypersaline conditions, of lactic acid bacteria isolated from seaweed
AU - Papadopoulou, Eleftheria
AU - Rodriguez de Evgrafov, Mari Cristina
AU - Kalea, Argyro
AU - Tsapekos, Panagiotis
AU - Angelidaki, Irini
PY - 2023
Y1 - 2023
N2 - Seaweed biomass has been proposed as a promising alternative carbon
source for fermentation processes using microbial factories. However,
the high salinity content of seaweed biomass is a limiting factor in
large scale fermentation processes. To address this shortcoming, three
bacterial species (Pediococcus pentosaceus, Lactobacillus plantarum, and Enterococcus faecium) were isolated from seaweed biomass and evolved to increasing concentrations of NaCl. Following the evolution period, P. pentosaceus reached a plateau at the initial NaCl concentration, whereas L. plantarum, and E. faecium
showed a 1.29 and 1.75-fold increase in their salt tolerance,
respectively. The impact that salt evolution had on lactic acid
production using hypersaline seaweed hydrolysate was investigated.
Salinity evolved L. plantarum produced 1.18-fold more lactic acid than the wild type, and salinity evolved E. faecium
was able to produce lactic acid, while the wild type could not. No
differences in lactic acid production were observed between the P. pentosaceus
salinity evolved and wild type strains. Evolved lineages were analyzed
for the molecular mechanisms underlying the observed phenotypes.
Mutations were observed in genes affecting the ion balance in the cell,
the composition of the cell membrane and proteins acting as regulators.
This study demonstrates that bacterial isolates from saline niches are
promising microbial factories for the fermentation of saline substrates,
without the requirement of previous desalination steps, while
preserving high final product yields.
AB - Seaweed biomass has been proposed as a promising alternative carbon
source for fermentation processes using microbial factories. However,
the high salinity content of seaweed biomass is a limiting factor in
large scale fermentation processes. To address this shortcoming, three
bacterial species (Pediococcus pentosaceus, Lactobacillus plantarum, and Enterococcus faecium) were isolated from seaweed biomass and evolved to increasing concentrations of NaCl. Following the evolution period, P. pentosaceus reached a plateau at the initial NaCl concentration, whereas L. plantarum, and E. faecium
showed a 1.29 and 1.75-fold increase in their salt tolerance,
respectively. The impact that salt evolution had on lactic acid
production using hypersaline seaweed hydrolysate was investigated.
Salinity evolved L. plantarum produced 1.18-fold more lactic acid than the wild type, and salinity evolved E. faecium
was able to produce lactic acid, while the wild type could not. No
differences in lactic acid production were observed between the P. pentosaceus
salinity evolved and wild type strains. Evolved lineages were analyzed
for the molecular mechanisms underlying the observed phenotypes.
Mutations were observed in genes affecting the ion balance in the cell,
the composition of the cell membrane and proteins acting as regulators.
This study demonstrates that bacterial isolates from saline niches are
promising microbial factories for the fermentation of saline substrates,
without the requirement of previous desalination steps, while
preserving high final product yields.
KW - Adaptive laboratory evolution
KW - Brown seaweed
KW - Lactic acid bacteria
KW - Salt tolerance
U2 - 10.1016/j.nbt.2023.03.001
DO - 10.1016/j.nbt.2023.03.001
M3 - Journal article
C2 - 36870677
SN - 1871-6784
JO - New Biotechnology
JF - New Biotechnology
ER -