Description:
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<jats:title>Abstract</jats:title>
<jats:p>Agri-food residues offer significant potential as a raw material for the production of <jats:sc>L</jats:sc>-lactic acid through microbial fermentation. <jats:italic>Weizmannia coagulans</jats:italic>, previously known as <jats:italic>Bacillus coagulans</jats:italic>, is a spore-forming, lactic acid-producing, gram-positive, with known probiotic and prebiotic properties. This study aimed to evaluate the feasibility of utilizing untreated citrus waste as a sustainable feedstock for the production of <jats:sc>L</jats:sc>-lactic acid in a one-step process, by using the strain <jats:italic>W. coagulans</jats:italic> MA-13. By employing a thermophilic enzymatic cocktail (Cellic CTec2) in conjunction with the hydrolytic capabilities of MA-13, biomass degradation was enhanced by up to 62%. Moreover, batch and fed-batch fermentation experiments demonstrated the complete fermentation of glucose into <jats:sc>L</jats:sc>-lactic acid, achieving a concentration of up to 44.8 g/L. These results point to MA-13 as a microbial cell factory for one-step production of <jats:sc>L</jats:sc>-lactic acid, by combining cost-effective saccharification with MA-13 fermentative performance, on agri-food wastes. Moreover, the potential of this approach for sustainable valorization of agricultural waste streams is successfully proven.</jats:p>
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<jats:title>Key points</jats:title>
<jats:p><jats:italic>• Valorization of citrus waste, an abundant residue in Mediterranean countries.</jats:italic></jats:p>
<jats:p><jats:italic>• Sustainable production of the L-( +)-lactic acid in one-step process.</jats:italic></jats:p>
<jats:p><jats:italic>• Enzymatic pretreatment is a valuable alternative to the use of chemical.</jats:italic></jats:p>
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<jats:title>Graphical Abstract</jats:title>
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