Cell immobilization studies using a cellulose-binding domain fused to PrtP in Lactococcus lactis

Area of Science:

• Biotechnology
• Microbial cell surface display
• Protein engineering

Background:

• Cell surface display is a powerful tool for immobilizing microbial cells.
• Lactococcus lactis cell wall anchors like PrtP, NisP, and AcmA are used for surface display.
• The cellulose-binding domain (CBD) of XylA can mediate binding to cellulosic materials.

Purpose of the Study:

• To investigate the efficiency of different Lactococcus lactis cell wall anchors fused to a cellulose-binding domain for cell immobilization onto cellulose.
• To evaluate the impact of sortase-mediated anchoring on cell immobilization efficiency.

Main Methods:

• Construction of fusion proteins involving the XylA CBD and Lactococcus lactis anchors (PrtP, NisP, AcmA) under the P45 promoter and Usp45 secretion signal.
• Expression and analysis of cell immobilization efficiency for different fusion constructs.
• Investigation of sortase enzyme's effect on the immobilization of CBD-PrtP fusion constructs.

Main Results:

• The fusion construct with the PrtP anchor exhibited the most efficient cell immobilization to cellulose.
• CBD-PrtP and CBD-NisP fusion constructs showed inefficient cell wall attachment, with proteins primarily found in the supernatant.
• Co-expression of sortase with the CBD-PrtP fusion did not significantly improve cell immobilization efficiency.

Conclusions:

• The PrtP anchor is a promising candidate for efficient cell immobilization to cellulose when fused with a CBD.
• Sortase-mediated anchoring does not necessarily enhance cell immobilization efficiency for CBD fusions in this context.
• Further optimization of anchor-cell wall interactions may be required for improved cell immobilization strategies.