Acetobacter xylinum Mutant with High Cellulose Productivity and an Ordered Structure

Area of Science:

• Microbiology
• Biochemistry
• Materials Science

Background:

• Acetobacter xylinum subsp. sucrofermentans BPR2001 produces bacterial cellulose and the polysaccharide acetan.
• UDP-glucose is the common precursor for both cellulose and acetan synthesis.
• Acetans role in cellulose fibril assembly is not fully understood.

Purpose of the Study:

• To develop a mutant strain of Acetobacter xylinum with improved cellulose production.
• To investigate the effect of reduced acetan production on cellulose structure and properties.

Main Methods:

• Isolation and characterization of a mutant strain (BPR3001A) from Acetobacter xylinum BPR2001.
• Quantification of bacterial cellulose and acetan production in parent and mutant strains.
• Analysis of cellulose structural properties including polymerization, crystallinity, and crystallite size.
• Measurement of Young's modulus of processed cellulose sheets.

Main Results:

• Mutant BPR3001A produced 65% more bacterial cellulose and 83% less acetan than the parent strain BPR2001.
• The cellulose produced by BPR3001A exhibited higher structural order, increased polymerization, crystallinity, and larger crystallite size.
• Processed cellulose from BPR3001A showed a higher Young's modulus compared to the wild strain.

Conclusions:

• Reduced acetan accumulation in mutant BPR3001A leads to enhanced production of structurally ordered bacterial cellulose.
• The improved cellulose structure likely results from unimpeded ribbon assembly of cellulose fibrils.
• This study demonstrates a strategy for improving bacterial cellulose quality through genetic modification.