Sorokin Dimitry Y, van Pelt Sander, Tourova Tatjana P, Muyzer Gerard
Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prospect 60-let Octyabrya 7/2, 117811 Moscow, Russia.
Appl Environ Microbiol. 2007 Sep;73(17):5574-9. doi: 10.1128/AEM.00342-07. Epub 2007 Jul 20.
The utilization of isobutyronitrile (iBN) as a C and N source under haloalkaline conditions by microbial communities from soda lake sediments and soda soils was studied. In both cases, a consortium consisting of two different bacterial species capable of the complete degradation and utilization of iBN at pH 10 was selected. The soda lake sediment consortium consisted of a new actinobacterium and a gammaproteobacterium from the genus Marinospirillum. The former was capable of fast hydrolysis of aliphatic nitriles to the corresponding amides and much-slower further hydrolysis of the amides to carboxylic acids. Its partner cannot hydrolyze nitriles but grew rapidly on amides and carboxylic acids, thus acting as a scavenger of products released by the actinobacterium. The soda soil consortium consisted of two Bacillus species (RNA group 1). One of them initiated nitrile hydrolysis, and the other utilized the hydrolysis products isobutyroamide (iBA) and isobutyrate (iB). In contrast to the actinobacterium, the nitrile-hydrolyzing soil Bacillus grew rapidly with hydrolysis products, but it was dependent on vitamins most probably supplied by its product-utilizing partner. All four bacterial strains isolated were moderately salt-tolerant alkaliphiles with a pH range for growth from pH 7.0 to 8.5 up to 10.3 to 10.5. However, both their nitrile hydratase and amidase activities had a near-neutral pH optimum, indicating an intracellular localization of these enzymes. Despite this fact, the study demonstrated a possibility of whole-cell biocatalytic hydrolysis of various nitriles at haloalkaline conditions.
研究了来自苏打湖沉积物和苏打土壤的微生物群落，在卤代碱性条件下将异丁腈（iBN）用作碳源和氮源的情况。在这两种情况下，都选择了一个由两种不同细菌组成的联合体，它们能够在pH值为10的条件下完全降解和利用iBN。苏打湖沉积物联合体由一种新的放线菌和一种来自海螺旋菌属的γ-变形菌组成。前者能够将脂肪族腈快速水解为相应的酰胺，而将酰胺进一步水解为羧酸的速度则慢得多。它的伙伴不能水解腈，但能在酰胺和羧酸上快速生长，因此充当了放线菌释放产物的清除剂。苏打土壤联合体由两种芽孢杆菌（RNA组1）组成。其中一种启动腈的水解，另一种利用水解产物异丁酰胺（iBA）和异丁酸盐（iB）。与放线菌不同，水解腈的土壤芽孢杆菌能与水解产物快速生长，但它很可能依赖于其利用产物的伙伴提供的维生素。分离出的所有四种细菌菌株都是中度耐盐嗜碱菌，生长的pH范围从pH 7.0至8.5到10.3至10.5。然而，它们的腈水合酶和酰胺酶活性的最适pH值都接近中性，表明这些酶定位于细胞内。尽管如此，该研究证明了在卤代碱性条件下对各种腈进行全细胞生物催化水解是可能的。
