Impact of olive mill wastewaters on the physiological behavior of a wild-type new Ganoderma resinaceum isolate

Environ Sci Pollut Res Int. 2021 Apr;28(16):20570-20585. doi: 10.1007/s11356-020-11835-4. Epub 2021 Jan 6.

Abstract

A new wild-type Ganoderma resinaceum isolate was cultivated on glucose-enriched liquid cultures with olive mill wastewaters (OMWs) in initial phenolic compounds concentrations 0.0 (control), 0.5, 0.8, and 1.5 g/l. The effect of the fungus on the reduction of phenolics and color was assessed, whereas biomass production, glucose consumption, intra-cellular (IPS) and extra-cellular (EPS) polysaccharides biosynthesis, antioxidant activity of the biomass, and laccase synthesis were monitored. Results showed that significant phenolic reduction (94.5%) and decolorization (76.5%) occurred, 14.6 g/l of biomass was produced, glucose was almost totally consumed, EPS were produced in sufficient amounts (0.79 g/l), whereas the presence of OMWs enhanced the synthesis of IPS (maximum absolute values 4.0-5.2 g/l corresponding to 35-42% w/w). Kinetic analysis demonstrated that EPS and IPS values fluctuated with time, regardless of the available amount of glucose in the media, showing a maximum in the 17th day of culture. Laccase was highly synthesized in the middle of the fermentation, reaching the maximum value of 14 U/ml. Little growth was however observed at 1.5 g/l phenolics. Strong correlation between total phenolic content and free radical scavenging activity has been noticed in the methanolic extracts of the mycelium. Results strongly suggest the potentiality of G. resinaceum utilization in the OMW waste treatment.

Keywords: Antioxidant activity; Biomass; Laccase; Phenolics; Polysaccharides; White-rot fungi.

MeSH terms

  • Ganoderma*
  • Industrial Waste
  • Kinetics
  • Olea*
  • Olive Oil
  • Wastewater

Substances

  • Industrial Waste
  • Olive Oil
  • Waste Water

Supplementary concepts

  • Ganoderma resinaceum