Enhanced Low-Temperature Corn Straw Degradation Using a Synthetic Microbial Mixture

Area of Science:

• Microbiology
• Environmental Science
• Biotechnology

Background:

• Lignocellulosic fibers in crop straw resist biodegradation, especially in cold climates, hindering utilization.
• Developing microbial solutions for low-temperature straw degradation is crucial for agricultural waste management in regions like northern China.

Purpose of the Study:

• To isolate and characterize low-temperature straw-degrading bacteria.
• To evaluate the efficacy of a synthetic microbial mixture for crop straw biodegradation at low temperatures.

Main Methods:

• Selective enrichment of microorganisms from straw-amended soils using lignocellulose as the sole carbon source.
• Isolation and identification of three bacterial strains: *Stenotrophomonas* sp. X24, *Flavobacterium* sp. X26, and *Erwiniaceae bacterium* X27.
• Assessment of straw degradation and cellulolytic enzyme activities (CMCase, FPase, β-glucosidase) using solid-state fermentation and optimized culture conditions.

Main Results:

• The isolated strains demonstrated growth and maize straw degradation between 4-20 °C.
• A synthetic three-strain mixture achieved a net straw degradation rate of 30.93 ± 1.05% at 12 °C over 45 days.
• Optimized culture conditions enhanced carboxymethyl cellulase activity (CMCase) to 24.51 ± 0.97 U/mL.

Conclusions:

• A synthetic microbial mixture of *Stenotrophomonas* sp. X24, *Flavobacterium* sp. X26, and *Erwiniaceae bacterium* X27 effectively degrades crop straw at low temperatures.
• This microbial consortium offers a promising solution for improving straw utilization and soil fertility in cold regions.
• The study highlights the potential of tailored microbial consortia for bioremediation and resource recovery in challenging environments.