During cell growth, proliferation, and metabolism, relative suspension state can be maintained through electrostatic forces between cells and intermolecular forces between proteins. It’s beneficial for cells to uptake of nutrients and substrates. The collection of cells by sedimentation at the end of cell culture or fermentation could significantly reduce the equipment and energy consumption required for centrifugal collection or plate and frame filter collection. Lipopolysaccharide (LPS) is a primary component of the cell membrane. Its structure and composition are directly related to cell auto-aggregation capacity, and consequently LPS plays a significant role in the cell sedimentation process for separating biomass and broth. In this study, Escherichia coli LGL4A06 with less LPS synthesis ability was constructed from E. coli LG101 through partially blocking the LPS synthesis pathway. Compared with the E. coli LG101, LPS content and the biomass dry weight (with the same cell density) of LGL4A06 decreased by 32.46% and 39.34%, respectively. The auto-aggregation rate of LGL4A06 reached 83.40% after 12 h of standing, which was 13.9 times higher than E. coli LG101. However, a low growth rate of LGL4A06 was observed. The effect of metal ions and temperatures on auto-aggregation was investigated at different ranges. In the presence of Ca2+ and Mg2+(10 mmol/L), the auto-aggregation rate of LGL4A06 was increased by 95.00% and 83.00%, respectively. No significant effect on cell auto-aggregation was observed with increasing temperature from 4 ℃ to 37 ℃. The present investigation focused on decreasing LPS content and enhancing the auto-aggregation efficiency of cells, which could facilitate the biomass separation process and reduce the time consumption of the downstream process during fermentation.
LI Jingfang
,
HAN Mengyuan
,
LI Mingxin
,
ZHANG Meng
,
TIAN Kangming
. Effects of deficiency in lipopolysaccharide synthesis on the cellular outer membrane functions[J]. Food and Fermentation Industries, 2023
, 49(24)
: 15
-20
.
DOI: 10.13995/j.cnki.11-1802/ts.036540
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