Simplified engineering design towards a competitive lipid-rich effluents valorization

Lucía Argiz; Ángeles Val Del Río; David Correa-Galeote; Belén Rodelas; Anuska Mosquera-Corral

doi:10.1016/j.jenvman.2022.115433

Simplified engineering design towards a competitive lipid-rich effluents valorization

J Environ Manage. 2022 Sep 1:317:115433. doi: 10.1016/j.jenvman.2022.115433. Epub 2022 Jun 9.

Authors

Lucía Argiz¹, Ángeles Val Del Río², David Correa-Galeote³, Belén Rodelas³, Anuska Mosquera-Corral²

Affiliations

¹ CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain. Electronic address: luciaargiz.montes@usc.es.
² CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain.
³ Department of Microbiology, Faculty of Pharmacy, University of Granada, 18001, Granada, Andalucía, Spain; Microbiology and Environmental Technology Section, Department of Microbiology, Faculty of Pharmacy, University of Granada, 18001, Granada, Andalucía, Spain.

PMID: 35751251
DOI: 10.1016/j.jenvman.2022.115433

Abstract

Medium- and long-chain fatty acids and glycerol contained in the oily fraction of many food-industry effluents are excellent candidates to produce biobased high-value triacylglycerides (TAGs) and polyhydroxyalkanoates (PHAs). The typical process configuration for TAGs recovery from lipid-rich streams always includes two steps (culture enrichment plus storage compounds accumulation) whereas, for PHAs production, an additional pretreatment of the substrate for the obtainment of soluble volatile fatty acids (VFAs) is required. To simplify the process, substrate hydrolysis, culture enrichment, and accumulation (TAG and PHA storage) were coupled here in a single sequencing batch reactor (SBR) operated under the double growth limitation strategy (DGL) and fed in pulses with industrial waste fish oil during the whole feast phase. When the SBR was operated in 12 h cycles, it was reached up to 51 wt % biopolymers after only 6 h of feast (TAG:PHA ratio of 50:51; 0.423 Cmmol_BIOP/Cmmol_S). Daily storage compound production was observed to be over 25% higher than the reached when enrichment and accumulation stages were carried in separate operational units. Increasing the feast phase length from 6 to 12 h (18 h cycle) negatively affected the DGL strategy performance and hence system storage capacity, which was recovered after also extending the famine phase in the same proportion (24 h cycle). Besides, the carbon influx during the feast phase was identified as a key operational parameter controlling storage compounds production and, together with the C/N ratio, culture selection. The different cycle configurations tested clearly modulated the total fungal abundances without no significant differences in the size of the bacterial populations. Several PHA and TAG producers were found in the mixed culture although the PHA and TAG productions were poorly associated with the increased relative abundances (RAs) of specific operational taxonomic units (OTUs).

Keywords: Bioprocess; Mixed microbial culture; Polyhydroxyalkanoate; Triacylglyceride; Waste lipids.

MeSH terms

Bioreactors* / microbiology
Carbon
Fatty Acids, Volatile
Industrial Waste
Polyhydroxyalkanoates*

Substances

Fatty Acids, Volatile
Industrial Waste
Polyhydroxyalkanoates
Carbon