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Enhanced fermentative lactic acid production from source-sorted organic household waste: Focusing on low-pH microbial adaptation and bio-augmentation strategy

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  • Zengshuai Zhang, Technical University of Denmark
  • ,
  • Panagiotis Tsapekos, Technical University of Denmark
  • ,
  • Merlin Alvarado-Morales, Technical University of Denmark
  • ,
  • Xinyu Zhu, Technical University of Denmark
  • ,
  • Athanasios Zervas
  • Carsten S. Jacobsen
  • Irini Angelidaki, Technical University of Denmark

Lactic acid (LA) production at low pH could significantly reduce the need for neutralizing agents, leading to reduction of operational costs. In the present study, LA production at acidic conditions was investigated using source-sorted organic household waste (SSOHW). Controlling the pH at low value (i.e. 5.0) and bio-augmenting with Pediococcus acidilactici led to a concentration of 39.3 ± 0.5 g-LA/L with a yield of 0.75 ± 0.02 g-LA/g-sugar. In contrast, secondary fermentation at higher pH level (i.e. 5.5 and 6.0) resulted in complete LA degradation. Subsequently, consecutive batch fermentations were conducted to adapt P. acidilactici to SSOHW and improve the LA production. Results showed that P. acidilactici could successively adapt in the SSOHW reaching a relative abundance above 2.8% at adaptation process. The added P. acidilactici ensured a high concentration of LA at three consecutive generations, achieving an increment above 18% compared to control test (abiotic augmentation). Moreover, adaptation processes (i.e. maintaining pH at 4.0 or stepwise decreasing the pH from 5.0 to 4.0) significantly improved LA concentration and productivity at the pH of 4.0. Overall, the results provide a promising method to reduce the LA production costs using residual resources.

Original languageEnglish
Article number152129
JournalScience of the total Environment
Publication statusPublished - Feb 2022

Bibliographical note

Publisher Copyright:
© 2021 The Authors

    Research areas

  • Acidic fermentation, Adaptation process, Lactic acid, Source-sorted organic household waste

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