Novel coaggregating microbial consortium: testing strength for field applications

Area of Science:

• Environmental microbiology
• Biotechnology

Background:

• Acinetobacter johnsonii S35 and Oligotropha carboxidovorans S23 exhibit coaggregation.
• Environmental stresses like nutrient deficiency can alter microbial cell surface properties and interactions.
• Understanding interaction stability is crucial for applications in waste stream remediation.

Purpose of the Study:

• To investigate the stability of Acinetobacter johnsonii S35 and Oligotropha carboxidovorans S23 coaggregation under various environmental stresses.
• To assess the impact of mineral deficiency and substrate shortage on microbial growth, cell surface hydrophobicity, and coaggregation ability.

Main Methods:

• Culturing of Acinetobacter johnsonii S35 and Oligotropha carboxidovorans S23 under varied conditions (mineral-deficient medium, supplemented Sterile Filtrate of Activated Sludge).
• Measurement of microbial growth, cell surface hydrophobicity, and aggregation index (AI).
• Comparative analysis of coaggregation behavior under control and stressed conditions.

Main Results:

• Acinetobacter johnsonii S35 growth was reduced in mineral-deficient medium, with decreased hydrophobicity but only a slight reduction in aggregation index (75-84% vs. 92% control).
• S35 grown on supplemented Sterile Filtrate of Activated Sludge showed good growth and formed stable coaggregates with S23.
• Coaggregation ability of S35 with S23 was maintained even in mineral-deficient medium and with supplemented Sterile Filtrate of Activated Sludge.

Conclusions:

• The coaggregation ability of Acinetobacter johnsonii S35 with Oligotropha carboxidovorans S23 is constitutive and not significantly impacted by tested environmental factors.
• These robust microbial interactions hold potential for developing stable consortia for environmental applications.
• Further research into suitable formulations for these environmentally relevant microbes is recommended.