Evaluation of the yield and heavy metal bioaccumulation in the fruit body of Pleurotus ostreatus grown on sugar mill wastewaters

Sugar mill wastewater (SMWW) is one of the agro-industrial wastewaters that is generated in huge quantities every year. In this study, the effect of substrate moistening with different SMWW concentrations on the cultivation cycle and yield of Pleurotus ostreatus and health risks potential were evaluated. Purposely, five different concentrations of SMWW including 0 (control using fresh water supply) 25, 50, 75, and 100% were tested as wetting agents in P. ostreatus cultivation. The yield and biological efficiency (BE%) increased with increasing concentration of SMWW. The yield of strain Homegreen (PO-Holl) increased from 118.01 +/- 4.2 g kg(-1) (control) to 235.0 +/- 8.5 g kg(-1) in 100SMW treatment, whereas that of strain HK-35 (PO-HK35) was increased from 196.5 +/- 4.8 g kg(-1) (control) to 239.2 +/- 4.5 g kg(-1) and 236.3 +/- 4.1 g kg(-1) in 25TP:75SMW and 100SMW treatments, respectively. However, the heavy metal accumulation by P. ostreatus strains was also strongly correlated to the increase in SMWW concentration. On the other hand, these values were below the recommended daily intake (RDI) set by the FAO/WHO. Moreover, the values of the Healthy Risk Index (HRI) of all heavy metals were less than 1. The results showed that the use of SMWW as a wetting agent can reduce the use of fresh water and inputs of additive materials in P. ostreatus cultivation, while keeping mushroom production safe and sustaining the management of such wastewaters.

Automated summary

This study evaluated the effect of different concentrations of sugar mill wastewater (SMWW) on the cultivation cycle, yield, and health risks of Pleurotus ostreatus. The results showed that increasing SMWW concentration increased the yield and biological efficiency of P. ostreatus. However, there was also an increase in heavy metal accumulation, although it remained below the recommended daily intake. Therefore, using SMWW as a wetting agent can reduce freshwater usage and the need for additive materials, while maintaining mushroom production safety.