Bioremediation of Cu and Zn by guinea fowl feather wastes and biodegradation of Cu- and Zn-polluted feathers by free and immobilized heavy-metal-tolerant bacterium Pseudochrobactrum sp. IY-BUK1

Abstract

One of the major pollutants generated from guinea fowl farms and slaughterhouses is guinea fowl feather (GFF) wastes. Chicken feathers are an important substrate for removing aqueous pollutants due to their structural characteristics, but the application of GFFs for such purposes has not been elucidated. This study was carried out to determine the potential of raw as well as chemically and physically pretreated GFFs in the bioremediation of copper (Cu) and zinc (Zn) from aqueous solutions and the subsequent biodegradation of Cu-and Zn-laden GFFs using free and immobilized heavy-metal-tolerant bacteria. Using atomic adsorption spectrometry, the ability of treated and untreated GFFs to adsorb Cu and Zn was determined, and the generated heavy-metal-laden GFFs were degraded using Pseudochrobactrum sp. IY-BUK1. The results revealed that under optimized conditions, acetone and autoclave pretreatment enhanced Cu and Zn removal by 40% within 6 h when compared with raw GFFs. Similarly, complete biodegradation of Cu-and Zn-laden GFFs was achieved at pH 8, with 2% inoculum size, and at 25EC using IY-BUK1 in 7 days. Upon optimization of physical and nutritional conditions, using one factor at a time and response surface methodology, the maximum keratinase activity was achieved at 30EC, with 3% inoculum size and 3.5% polluted GFF concentration in 3 h. The degradation and keratinase activity were further enhanced by 50% by the immobilization of Pseudochrobactrum sp. IY-BUK1 cells compared with free cells. Thus, GFFs can act as good biosorbents, and together with IY-BUK1, the use of GFFs can be an alternative approach to dispose of GFFs, thus preventing environmental pollution via bioremediation.

Oxidation of Ammonia in Fish Ponds to Nitrates Using Free and Immobilized Nitrifying Bacteria

“…Immobilization of nitrifying bacteria cells was carried out using gellan gum following the method described by Yusuf et al (Yusuf et al, 2019;Yusuf & Sharu, 2022). Initially, gellan gum (0.75% w/v) was added to 100 ml of deionized water and heated to 75°C to dissolve the gum completely.…”