Fed batch bioconversion of 2-propanol by a solvent tolerant strain of Alcaligenes faecalis entrapped in Ca-alginate gel.
A gram-negative, rod-shaped, aerobe, capable of converting 2-propanol (isopropanol, IPA) to acetone was isolated from an oil/sump, and identified by 16 S rDNA analysis as Alcaligenes faecalis. Investigations showed this strain to be extremely solvent-tolerant and it was subsequently named ST1. In this study, A. faecalis ST1 cells were immobilized by entrapment in Ca-alginate beads (3 mm in diameter), and used in the bioconversion of high concentration IPA. The biodegradation rates and the corresponding microbial growth inside the beads were measured at four different IPA concentration ranges from 2 to 15 g l(-1). The maximum cell concentration obtained was 9.59 g dry cell weight (DCW) l(-1) medium which equated to 66 g DCW l(-1) gel, at an initial IPA concentration of 15 g l(-1) after 216 h of incubation. A maximum biodegradation rate of 0.067 g IPA g cells(-1) h(-1) was achieved for 5 g l(-1) IPA where an increase in IPA concentration to 38 g l(-1) caused reduction in bead integrity. A modified growth medium was developed which allowed repeated use of the beads for more than 42 days without any loss of integrity and continued bioconversion activity.
Mohammad
Balsam T
BT
Chemical Engineering Laboratory, Faculty of Sciences, University of La Coruna, Campus da Zapateira, 15071 La Coruna, Spain. balsamt@hotmail.com
Bustard
Mark T
MT
D019840:2-Propanol / Q000378:metabolism* / Q000494:pharmacology*; D000096:Acetone / Q000378:metabolism / Q000494:pharmacology; D042481:Alcaligenes faecalis / Q000187:drug effects* / Q000378:metabolism*; D000464:Alginates; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001711:Biotransformation; D018914:Cells, Immobilized / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008863:Microspheres; D012997:Solvents / Q000494:pharmacology
D000464:Alginates; D000900:Anti-Bacterial Agents; D003470:Culture Media; D005782:Gels; D006603:Hexuronic Acids; D012997:Solvents; D000096:Acetone; D020723:Glucuronic Acid; D019840:2-Propanol