Effect of hydraulic retention time on lactic acid production and granulation in an up-flow anaerobic sludge blanket reactor

Bioresour Technol. 2014 Aug:165:158-61. doi: 10.1016/j.biortech.2014.03.097. Epub 2014 Mar 27.

Abstract

In the present work, lactic acid (LA) production performance with granulation was investigated at various hydraulic retention times (HRTs), 8-0.5h. Glucose was used as a feedstock, and anaerobic mixed cultures were inoculated in an up-flow anaerobic sludge blanket reactor. As HRT decreased, the average diameter and hydrophobicity of the granules increased from 0.31 to 3.4mm and from 17.5% to 38.3%, respectively, suggesting the successful formation of granules. With decreasing HRT, LA productivity increased up to 16.7gLA/L-fermenter/h at HRT 0.5h. The existence of rod-shaped organisms with pores and internal channels at granule surface was observed by scanning electron microscope. Next generation sequencing revealed that Lactobacillus was the dominant microorganism, accounting for 96.7% of total sequences, comprising LA-producing granules.

Keywords: Granulation; Hydraulic retention time (HRT); Hydrophobicity; Lactic acid; Up-flow anaerobic sludge blanket reactor (UASBr).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis
  • Bacteria / metabolism
  • Bioreactors / microbiology*
  • Hydrogen-Ion Concentration
  • Hydrophobic and Hydrophilic Interactions
  • Lactic Acid / biosynthesis*
  • Particle Size
  • Rheology*
  • Sewage / microbiology*
  • Species Specificity
  • Time Factors

Substances

  • Sewage
  • Lactic Acid