Abstract

Antibiotic resistance and the economic burden of Avian Pathogenic Escherichia coli (APEC) infections underscore the need for sustainable alternatives to conventional antibiotics. This study aimed to investigate potential of Curcuma longa pomace (CLP) as antibacterial and antibiofilm agent against APEC, and to develop microcapsules containing CLP to enhance stability during storage. The formulation ME2.3, consisting of a deep eutectic solvent (menthol and lactic acid) and surfactants (Cremophor RH40 and Labrasol), exhibited potent antibacterial activity, with minimum inhibitory concentration (MIC) values of 8–16 mg/mL and minimum bactericidal concentration (MBC) of 32 mg/mL. Scanning electron microscopy revealed significant structural damage in APEC cells treated with 2×MIC, including surface roughening and cell lysis. The extract at 1/2×MIC significantly inhibited biofilm formation, ranging from 54-88%, compared with the control. Interestingly, 93-99% of the viable cells embedded in mature biofilms were eradicated after treatment with 16×MIC. Microcapsules of ME2.3 fabricated with sodium alginate (CLPSA/ME2.3) demonstrated high encapsulation efficiency (99%) and controlled curcuminoid release under simulated gastrointestinal fluids. These microcapsules preserved curcuminoid stability under acidic, bile, and enzymatic conditions while maintaining antioxidant efficacy over 90 days. This study highlights microencapsulated CLP as a promising sustainable strategy to combat APEC infections in poultry.