The disclosure relates to mutant gene(s) that confer upon microorganisms that express them an improved capacity to utilize xylose and improved capacity to co-utilize glucose and xylose thereby resulting in improved growth of the microorganism. Further encompassed are methods of producing fatty acids and fatty acid derivatives from cellulosic biomass, xylose, and/or a glucose/xylose mix by employing the host cells expressing the engineered XylR variants and compositions of biologically produced fatty acids and fatty acid derivatives.

The disclosure relates to mutant gene(s) that confer upon microorganisms that express them an improved capacity to utilize xylose and improved capacity to co-utilize glucose and xylose thereby resulting in improved growth of the microorganism. Further encompassed are methods of producing fatty acids and fatty acid derivatives from cellulosic biomass, xylose, and/or a glucose/xylose mix by employing the host cells expressing the engineered XylR variants and compositions of biologically produced fatty acids and fatty acid derivatives.

Provided are an immobilized enzyme and an application thereof in continuous production. The immobilized enzyme is a Polyethyleneimine (PEI)-modified immobilized enzyme, and includes: an enzyme, which includes Amine Dehydrogenase (AmDH) and/or Formate Dehydrogenase (FDH); and a carrier, which is a cyanuric chloride-activated amino carrier. The problem in the prior art of poor performance of an immobilized enzyme is solved, the catalytic activity and reusability of the immobilized enzyme are improved, and the immobilized enzyme is suitable for the field of enzyme immobilization.