Investigation of Cr(VI) reduction and Cr(III) immobilization mechanism by planktonic cells and biofilms of Bacillus subtilis ATCC-6633

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• 作者：Xiaohong Pan^a ; ^b ; Zunjing Liu^b ; Zhi Chen^a ; ^b ; Yangjian Cheng^b ; Danmei Pan^b ; Jiening Shao^c ; Zhang Lin^b ; ^{zlin@fjirsm.ac.cn" class="auth_mail} ; Xiong Guan^a ; ^{guanxfafu@126.com" class="auth_mail}
• 关键词：Bacillus subtilis ; Biofilm ; Chromium ; Immobilization ; Reduction
• 刊名：Water Research
• 出版年：15 May, 2014
• 年：2014
• 卷：55
• 期：Complete
• 页码：21-29
• 全文大小：1703 K

文摘

In this study, we investigated the Cr(VI) uptake mechanism of planktonic cells and biofilms of Bacillus subtilis (B. subtilis) ATCC-6633. Data showed that the effect of planktonic cells on the Cr(VI) uptake was quite different from that of biofilms. Planktonic cells had strong ability of Cr(VI) reduction, while biofilms possessed a great potential of Cr(III) immobilization. For planktonic cells, 100聽mg/L Cr(VI) could be completely reduced. Both exopolymeric substances and cytoplasmic extracts contributed to high capacity of Cr(VI) reduction. After the reduction, noticeable Cr(III) precipitates were accumulated on bacterial surfaces, but 37.5% Cr(III) still remained in the supernatant. For biofilms, the biofilm debris became the main active ingredient of the Cr(VI) reduction. However, only 20聽mg/L Cr(VI) could be reduced probably because of unavailability of reducing active sites during the biofilm formation. Further studies showed that biofilms had a better Cr(III) immobilization capacity than planktonic cells with 100% Cr(III) immobilized. Moreover, for the first time, we proposed a strategy combining the advantages of both planktonic cells and biofilms, and a successful Cr(VI) removal from typical Cr(VI)-containing plating wastewater was achieved through a 10-L pilot-scale experiment.