Bioflocculants Produced by Bacterial Strains Isolated from Palm Oil Mill Effluent for Application in the Removal of Eriochrome Black T Dye from Water.

Syed Zaghum Abbas,Shareefa Ahmed Alshareef,Masoom Raza Siddiqui,Moonis Ali Khan,Yang-Chun Yong,Marta Otero,Mohd Rafatullah,Afnan Ali Hussain Hakami

doi:10.3390/polym12071545

Syed Zaghum Abbas, Shareefa Ahmed Alshareef + Show 6 more

Open Access

https://doi.org/10.3390/polym12071545

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Abstract

Four strains of bioflocculant-producing bacteria were isolated from a palm oil mill effluent (POME). The four bacterial strains were identified as Pseudomonas alcaliphila (B1), Pseudomonas oleovorans (B2), Pseudomonas chengduensis (B3), and Bacillus nitratireducens (B4) by molecular identification. Among the four bacterial strains, Bacillus nitratireducens (B4) achieved the highest flocculating activity (49.15%) towards kaolin clay suspension after eight hours of cultivation time and was selected for further studies. The optimum conditions for Eriochrome Black T (EBT) flocculation regarding initial pH, type of cation, and B4 dosage were determined to be pH 2, Ca2⁺ cations, and a dosage of 250 mL/L of nutrient broth containing B4. Under these conditions, above 90% of EBT dye removal was attained. Fourier transform infrared spectroscopic (FT-IR) analysis of the bioflocculant revealed the presence of hydroxyl, alkyl, carboxyl, and amino groups. This bioflocculant was demonstrated to possess a good flocculating activity, being a promissory, low-cost, harmless, and environmentally friendly alternative for the treatment of effluents contaminated with dyes.

Highlights

Dyes are chemical compounds that show affinity towards the applied substrate, such as surfaces or fabrics to impart color
The National Center for Biotechnology Information (NCBI) BLAST search of the 16S rRNA gene against GenBank showed that bacterial strain
The NCBI BLAST search of the 16S rRNA gene against GenBank showed that bacterial strain B1 was The

Summary

Introduction

Dyes are chemical compounds that show affinity towards the applied substrate, such as surfaces or fabrics to impart color. Certain kinds of dyes can be toxic, carcinogenic, teratogenic, or mutagenic to different microorganisms, animals, and even humans; are persistent environmental pollutants; and may cross entire food chains, providing biomagnification. The presence of dyes from the textile industry in the aquatic environment is greatly noticeable and unpleasant, even at low concentrations. Conventional wastewater treatments do not guarantee complete removal of dyes due to factors, such as color fastness, stability, and resistance to degradation. Physicochemical treatments are applied in industries to eliminate dyes from the wastewater, these treatment methods are normally costly and Polymers 2020, 12, 1545; doi:10.3390/polym12071545 www.mdpi.com/journal/polymers

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