Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor

Abstract

Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH)SO. Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g (dry basis) was obtained after 7 days of fermentation.

Lipase production by solid‐state fermentation of olive pomace in tray‐type and pressurized bioreactors

“…Also, no significant differences in MC of fermented substrate at different conditions of air pressure and aeration rate were observed. Similarly, Oliveira et al . found equal lipase production by SSF in a packed‐bed bioreactor, using 25 g of substrate, at aeration rates of 0.05 and 0.1 L min ‐1 .…”

“…SSF experiments were performed using OP mixed with WB, in a ratio of 1:1 (w/w, dry basis), 0.0133 g of (NH 4 ) 2 SO 4 per gram of dry solid substrate, 33.33 μL g ‐1 of inoculum solution with 10 7 spores mL ‐1 . The mixture of OP with WB resulted in optimum MC, of around 60% (w/w), without the need for its adjustment.…”

“…The mixture of OP with WB resulted in optimum MC, of around 60% (w/w), without the need for its adjustment. Fermentations were carried out at 30 °C in an incubator for 7 days without agitation , . SSFs were performed using sterilized (121 °C, 200 kPa for 15 min) and unsterilized substrate.…”

Lipase Production by Solid-State Cultivation of Thermomyces Lanuginosus on By-Products from Cold-Pressing Oil Production

“…Many papers on lipase production using solid-state cultivation of fungi on different low-cost media derived from agroindustry residues have been published thus far, although no data of its successful commercialization on a large scale are available. With the purpose of lipase production, Aspergillus niger was cultivated on a variety of agricultural wastes [6][7][8][9], Rhizopus oryzae on sugarcane bagasse [10], Aspergillus species on olive pomace [11,12], Trichoderma strains on oil-palm fruit-bunch medium [13], Penicillium camemberti KCCM 11268 on wheat bran [14], Schizophyllum commune ISTL04 on Leucaena leucocephala seeds [15], etc.…”

From flasks to single used bioreactor: Scale-up of solid state fermentation process for metabolites and conidia production by Trichoderma asperellum

“…Therefore, the lipase activity may not be oxygen-limited. Oliveira et al (2017) have reported an improvement in lipase activity in a culture of Aspergillus ibericus using wheat bran with 10% of olive oil as substrate applying an aeration rate of 2 mL min −1 g −1 . The authors reported that an aeration rate above 8 mL min −1 g −1 also has a negative effect on lipase activity and fungal growth was observed when they tested the SSF without aeration.…”