Microbial consortium enrichment with alkaline-treated eucalyptus kraft lignin promotes selective bacterial diversity

Author(s)

Pereira, Alzira Aparecida ; Batista, Ubiratan da Silva ; Yaverino-Gutierrez, Mario Alberto ; Ascencio, Jesus Jimenez ; Ferraz, Andre ; Chandel, Anuj Kumar

• Document type: Journal article
• Source: BIOMASS & BIOENERGY; v. 193, p. 10-pg., 2025-01-03.

Abstract

Lignin, a complex and recalcitrant macromolecule, poses a significant challenge for microbial degradation. However, its breakdown is essential for advancing lignin valorization in biorefineries. This study developed a microbial consortium enriched over nine months with alkaline-treated eucalyptus kraft lignin as sole carbon source to investigate its lignin-degrading potential. Optimal conditions for the alkaline treatment of eucalyptus kraft lignin -10 % (w/v) lignin, 30 % (w/w) NaOH, for 45 min at 150 degrees C- enhanced the soluble lignin fraction at neutral pH, which served as the carbon source for microbial metabolism. Analysis of the consortium's bacterial composition through 16S rRNA gene sequencing revealed shifts in bacterial diversity before and after lignin enrichment. The enriched consortium exhibited a significant increase in the phylum Pseudomonadota (86.4), especially in genera such as Hyphomicrobium (13.1 %), Sphingobium (10.7 %), Roseomonas (10.3 %), Altererythrobacter (4.7 %), Beijerinckia (4.4 %), Pseudomonas (3.8 %), and Agrobacterium (3.5 %), known for their ligninolytic abilities. After enrichment, the consortium demonstrated efficient growth in the alkali-treated lignin, with preferential consumption of the low-molar-mass fractions. These findings illustrate the consortium's adaptability to selective pressure from lignin as a carbon source, highlighting specific microbial groups for lignin bioconversion applications and offering insights to enhance bacterial lignin degradation pathways. (AU)

• FAPESP's process: 22/13184-1 - Lignin-derived catalyst ink for printed electrodes
• Grantee: Anuj Kumar
• Support Opportunities: Regular Research Grants
• FAPESP's process: 22/05214-8 - Bacterial valorization of kraft lignin for PHA production through metagenomic sequencing of pulp-ligcon microbial community
• Grantee: Alzira Aparecida Pereira
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 20/12559-6 - Bio-valorization of lignin from Kraft pulp mills through establishment of Pulp-Ligcon metagenome sequencing
• Grantee: Anuj Kumar
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 23/09410-9 - Bacterial valorization of pre-treated kraft lignin for biolipids production through metagenomic approach
• Grantee: Ubiratan da Silva Batista
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 23/12273-3 - Exploring anaerobic digestion for biogas production from native kraft lignin, depolymerized lignin, and delignified eucalyptus sawdust
• Grantee: Mario Alberto Yaverino Gutierrez
• Support Opportunities: Scholarships in Brazil - Master