Characterization of Acrylamidase Isolated from a Newly Isolated Acrylamide-Utilizing Bacterium, Ralstonia eutropha AUM-01

Abstract

A mesophilic bacterium capable of utilizing acrylamide was isolated, AUM-01, from soil collected from leaf litter at Picnic Point on the UW-Madison campus. In minimal medium with acrylamide as the sole carbon and nitrogen source, a batch culture of AUM-01 completely converted 28.0 mM acrylamide to acrylic acid in 8 h and reached a cell density of 0.3 (A₆₀₀)). Afterward all the acrylic acid was degraded by 20 h with the cell density increasing to 1.9 (A₆₀₀). The acrylamide-utilizing bacterium was identified as Ralstonia eutropha based on morphological observations, the BiOLOG GN2 MicroPlate™ identification system for Gram-negative bacteria, and additional physiological tests. An acrylamidase that hydrolyzes acrylamide to acrylic acid was purified from the strain AUM-01. The molecular weight of the enzyme from AUM-01 was determined to be 38 kDa by SDS-PAGE. The enzyme had pH and temperature optima of 6.3 and 55°C, and the influence of different metals and amino acids on the ability of the purified protein to transform acrylamide to acrylic acid was evaluated. The enzyme from AUM-01 was totally inhibited by ZnSO₄ and AgNO₃.

Transfer and degradation of polyacrylamide-based flocculants in hydrosystems: a review

“…Ralstonia eutropha (Cha and Chambliss 2011) or Arthrobacter strains (Yamada et al 1979). The concentration of AMD that can be tolerated and degraded depends on the bacterial strain.…”

A high-throughput solid phase screening method for identification of lignocellulose-degrading bacteria from environmental isolates

“…Another type of solidifying agent commonly used in microbial and molecular biology laboratories is acrylamide. Although microbes capable of acrylamide depolymerization have been reported (Cha and Chambliss 2011), they appear to be uncommon in nature. Previous reports have utilized acrylamide as an encapsulation matrix for E. coli, without loss of metabolic activity (Tosa et al 1974).…”

Isolation and characterization of an acrylamide‐degrading yeast Rhodotorula sp. strain MBH23 KCTC 11960BP

“…A previous study reported that Pseudomonas stutzeri shows an optimum growth at 440 mg l -1 acrylamide [19], while Ralstonia eutropha TDM-3 can utilize up to 780 mg l -1 acrylamide [17]. Ralstonia eutropha AUM-01, however, can utilize up to 1990 mg l -1 acrylamide as the sole carbon and nitrogen source [18]. Bacillus cereus strain DRY135 shows optimum growth at between 1000 and 2000 mg l -1 acrylamide [21].…”

“…Acrylamide degradation generally follows an acrylic acid intermediate formation and this is true in this yeast strain as well as in A. oryzae [25] and in other bacteria such as Pseudomonas stutzeri [17], Bacillus cereus strain DRY135 [21], Ralstonia eutropha AUM-01 [18] and Pseudomonas sp. strain DRYJ7 [22].…”

“…In view of the fact that acrylamide is a neurotoxicant (carcinogen and teratogen), it is a hazardous compound that must be removed from the environment. Several microbes capable of utilizing acrylamide as a source of carbon and nitrogen have been isolated, for example: Klebsiella pneumonia [15], Helicobacter pylori [16], Ralstonia eutropha [17,18], Rhodococcus rhodochrous [19], Pseudomonas stutzeri [20], Bacillus cereus [21], Pseudomonas sp. [22], Pseudomonas chlororaphis [23], Pseudonocardia thermophila [24] and the fungi Aspergillus oryzae [25].…”