Klebsiella pneumoniae metabolites enhance Microcystis aeruginosa biomass flocculation

ABSTRACT

Microcystis aeruginosa is a common aquatic toxin-producing cyanobacterium. This study explores M. aeruginosa biomass recovery using bioflocculation. Bioflocculants produced by Klebsiella pneumoniae significantly enhanced aquatic M. aeruginosa flocculation efficiency. Under neutral and acidic conditions, flocculation efficiency reached 90%, whereas flocculation efficiency was 75% under alkaline conditions. M. aeruginosa flocculation was ion dependent, and Ca²⁺ was determined to be the most effective cationic inducer. Negatively charged proteoglycans were identified as the being the functional components in the flocculants. Optimal conditions for M. aeruginosa flocculation were determined using response surface methodology and are as follows: (1) K. pneumoniae bioflocculant dose, 13.3 mg/L; (2) flocculation time, 1.6 hours; and (3) pH = 5 for flocculation of 10⁹ cells per litre. Bioflocculation using K. pneumoniae represents a promising method to control development of M. aeruginosa blooms. Further in-field investigations are necessary to fully assess its potential.

KEYWORDS:

• Bioflocculation
• biomass recovery
• Klebsiella pneumoniae
• Microcystis aeruginosa
• response surface methodology

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors wish to thank the National Natural Science Foundation of China [grant numbers 51238001 and 51478096] for their financial supports.