The role of Serendipita indica and Lactobacilli mixtures on mitigating mycotoxins and heavy metals\u2019 risks of contaminated sewage sludge and its composts

Nesrine H Youssef,Mayada A Sabra,Hayssam M Ali,Nader R Abdelsalam,Asma A Al-Huqail

doi:10.1038/s41598-020-71917-8

Nesrine H Youssef, Mayada A Sabra + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-71917-8

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Abstract

Accumulation of the Municipal Sewage Sludge (MSS) is considered as one of the most harmful renewable ecological and human health problems. MSS is a renewable resource that could be used as a soil organic amendment. This study aims to reduce the Heavy Metals (HMs) from the sludge content and sludge compost. Furthermore, this study is considered the first to assess the mycotoxins content in sludge and sludge compost via a new biological treatment using the fungus Serendipita indica or a mixture of lactic acid bacteria, thus providing safer nutrients for the soil amendment for a longer time and preserving human health. The HMs and mycotoxins were determined. The results exhibited that the biotic remediation of bio-solid waste and sewage sludge compost succeeded; a new bio-treated compost with a very low content of heavy metals and almost mycotoxins-free contents was availed. Also, the results indicated that the Lactobacilli mixture realized the best results in reducing heavy metals contents and mycotoxins. Afterward, S. indica. biotic remediation of bio-solid waste and sewage sludge compost minimized the health risk hazards affecting the human food chain, allowing for the different uses of sludge to be safer for the environment.

Highlights

Accumulation of the Municipal Sewage Sludge (MSS) is considered as one of the most harmful renewable ecological and human health problems
The novelty of this study stems from the fact that is the first time to use this fungus and/or a mixture of two LAB bacteria as bio-removal agents for heavy metals and mycotoxins in MSS; we aimed to reduce the harmful effects of MSS compost, which is used in agriculture, to minimize its harmful effects on soils and to safely modify its use as a biofuel in a biotic manner to prevent adverse effects on the environment, underground water, air, vegetation, animals, and humans
The current results showed the difference in pH values significantly affected the S. indica growth and pH value 4 achieved the highest mass mat growth (9.72 g)

Summary

Introduction

Accumulation of the Municipal Sewage Sludge (MSS) is considered as one of the most harmful renewable ecological and human health problems. The novelty of this study stems from the fact that is the first time to use this fungus and/or a mixture of two LAB bacteria as bio-removal agents for heavy metals and mycotoxins in MSS; we aimed to reduce the harmful effects of MSS compost, which is used in agriculture, to minimize its harmful effects on soils and to safely modify its use as a biofuel in a biotic manner to prevent adverse effects on the environment, underground water, air, vegetation, animals, and humans. Our choice of these bacteria mixture and fungus was based on their known efficacies according to literature, our pilot experiment, and their beneficial effects to soil and plants

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