title: Encapsulation of Pannonibacter phragmitetus LSSE-09 in alginate-carboxymethyl cellulose capsules for reduction of hexavalent chromium under alkaline conditions.
abstract: Cr(VI) was efficiently reduced to Cr(III) by Pannonibacter phragmitetus LSSE-09 encapsulated in liquid-core alginate-carboxymethyl cellulose capsules under alkaline conditions. Taking into account the physical properties of the capsules, the activity of encapsulated cells, and total Cr(III) concentration in the supernatant, optimal conditions (0.5% w/v sodium alginate; 2% w/v sodium carboxymethyl cellulose; 0.1 M CaCl₂; 30-min gelation time) for LSSE-09 encapsulation were determined. At optimal conditions, a relatively high reduction rate of 4.20 mg g ((dry weight))⁻¹ min⁻¹ was obtained. Total Cr(III) concentration in the supernatant was significantly decreased after reduction, because 63.7% of the formed soluble organo-Cr(III) compounds compared with those of free cells were captured by the relatively smaller porous structure of alginate capsules. The optimal pH value (9.0) for Cr(VI) reduction was not changed after encapsulation. In addition, encapsulated LSSE-09 showed no appreciable loss in activity after eight repeated cycles at 37°C, and 85.7% of its initial activity remained after 35-day storage at 4°C. The results suggest that encapsulated LSSE-09 in alginate-carboxymethyl cellulose capsules has potential biotechnological applications for the detoxification of Cr(VI)-contaminated wastewater.
authors: Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Bei Er Tiao, Zhong Guan Cun, Haidian District, Beijing 100190, China.
authors: Lin
authors: L
authors: Xu
authors: Mingfang
authors: M
authors: Luo
authors: Liangrong
authors: L
authors: Yang
authors: Xuetuan
authors: X
authors: Wei
authors: Xing
authors: X
authors: Lin
authors: Huizhou
authors: H
authors: Liu
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002857:Chromium / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D041902:Rhodobacteraceae / Q000378:metabolism*
chemical_list: D000464:Alginates; D002857:Chromium; C074702:chromium hexavalent ion; D002266:Carboxymethylcellulose Sodium