Get access

Influence of the Metabolism Pathway on Lactic Acid Production from Hemicellulosic Trimming Vine Shoots Hydrolyzates Using Lactobacillus pentosus

Authors

  • Guadalupe Bustos,

    1. Departmento de Ingeniería Química, Universidad de Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Spain
    Search for more papers by this author
  • Ana Belén Moldes,

    1. Departmento de Ingeniería Química, Universidad de Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Spain
    Search for more papers by this author
  • José Manuel Cruz,

    1. Departmento de Ingeniería Química, Universidad de Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Spain
    Search for more papers by this author
  • José Manuel Domínguez

    Corresponding author
    1. Departmento de Ingeniería Química, Universidad de Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Spain
    • Departmento de Ingeniería Química, Universidad de Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Spain
    Search for more papers by this author

Abstract

Hemicellulosic hydrolyzates from trimming wastes of vine shoots were proposed as a carbon source for lactic acid production by Lactobacillus pentosus CECT-4023T (ATCC-8041). These hydrolyzates are composed mainly of glucose (12.0 g/L), xylose (17.5 g/L) and arabinose (4.3 g/L). Acetic acid, the main subproduct, started to be produced after all of the glucose was completely depleted, showing that the acetic acid coproduction came only from the xylose and arabinose consumption. In the absence of glucose, the L. pentosus pathway shifts from homo to heterofermentative. Thus, L. pentosus can be considered a facultative heterofermentative organism, degrading hexoses (glucose) via the Embden-Meyerhoff-Parnas pathway and pentoses (xylose and arabinose) via the phosphoketolase pathway. Hydrolyzates were vacuum evaporated to increase the initial sugars concentration up to 35.4 g/L of glucose, 52.3 g/L of xylose, and 13.0 g/L of arabinose. Under these conditions the lactic acid concentration reached 46.0 g/L (QP = 0.933 g/L·h, YP/S = 0.78 g/g; YP/S theoretical = 91.7%) and a clear product inhibition was observed. Additional experiments with synthetic sugars, in the absence of inhibitory compounds, indicate that this inhibition must be attributed to the metabolic pathway but not to the inhibitory compounds present in the fermentation broth.

Ancillary