Adaptive laboratory evolution of nanocellulose-producing bacterium

Area of Science:

• Biotechnology
• Microbial Engineering
• Biomaterials Science

Background:

• Komagataeibacter hansenii produces bacterial nanocellulose from glucose.
• Corn stover pretreatment liquid contains phenolic inhibitors that hinder bacterial growth and nanocellulose production.
• Direct utilization of glucose in pretreatment liquid is challenging due to toxic lignin-derived phenolics like vanillin and ferulic acid.

Purpose of the Study:

• To adapt Komagataeibacter hansenii to utilize glucose present in corn stover pretreatment liquid for bacterial nanocellulose production.
• To overcome phenolic inhibition in lignocellulosic hydrolysates.
• To establish pretreatment liquid as a viable feedstock for bioproduct generation.

Main Methods:

• Adaptive laboratory evolution (ALE) involving 12 rounds of culturing K. hansenii in increasing concentrations of corn stover pretreatment liquid.
• Culturing experiments using standard Hestrin and Schramm (HS) medium and pretreated liquid.
• Treatment of pretreatment liquid with activated charcoal to remove inhibitors.

Main Results:

• ALE successfully generated a K. hansenii strain resistant to phenolic inhibitors.
• The adapted strain produced bacterial nanocellulose directly from corn stover pretreatment liquid.
• The produced nanocellulose exhibited properties comparable to that from standard media.
• The adapted strain could also utilize xylose present in the pretreatment liquid.

Conclusions:

• Adaptive laboratory evolution is an effective strategy to overcome inhibitor toxicity in lignocellulosic hydrolysates.
• Corn stover pretreatment liquid can be a valuable, sustainable resource for bacterial nanocellulose production.
• This adapted strain enables the conversion of dilute glucose into a concentrated, value-added bioproduct, facilitating waste stream valorization.