Faculty of Technical Sciences

TY - JOUR

T1 - Enhanced fermentative lactic acid production from source-sorted organic household waste

T2 - Focusing on low-pH microbial adaptation and bio-augmentation strategy

AU - Zhang, Zengshuai

AU - Tsapekos, Panagiotis

AU - Alvarado-Morales, Merlin

AU - Zhu, Xinyu

AU - Zervas, Athanasios

AU - Jacobsen, Carsten S.

AU - Angelidaki, Irini

N1 - Publisher Copyright: © 2021 The Authors

PY - 2022/2

Y1 - 2022/2

N2 - 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.

AB - 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.

KW - Acidic fermentation

KW - Adaptation process

KW - Lactic acid

KW - Source-sorted organic household waste

UR - http://www.scopus.com/inward/record.url?scp=85120704342&partnerID=8YFLogxK

U2 - 10.1016/j.scitotenv.2021.152129

DO - 10.1016/j.scitotenv.2021.152129

M3 - Journal article

C2 - 34863737

AN - SCOPUS:85120704342

VL - 808

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

M1 - 152129

ER -