You are here:
EFFECTS OF A LIGNIN PEROXIDASE-EXPRESSING RECOMBINANT STREPTOMYCES LIVIDANS TK23.1 ON BIOGEOCHEMICAL CYCLING AND THE NUMBERS AND ACTIVITIES OF MICROORGANISMS IN SOIL
Citation:
Crawford, D., J. Doyle, Z. Wang, C. Hendricks, S. Bentjen, H. Bolton, Jr., J. Frederickson, AND B. Bleakley. EFFECTS OF A LIGNIN PEROXIDASE-EXPRESSING RECOMBINANT STREPTOMYCES LIVIDANS TK23.1 ON BIOGEOCHEMICAL CYCLING AND THE NUMBERS AND ACTIVITIES OF MICROORGANISMS IN SOIL. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/049 (NTIS PB93167302).
Description:
A recombinant actinomycete, Streptomyces lividans TK23.1, expressing a pIJ702-encoded extracellular lignin peroxidase gene cloned from the chromosome of Streptomyces virodosporus T7A, was released into soil in flask- and microcosm-scale studies to determine its effects on humification and elemental cycling, and on the numbers, types, and activities of microorganisms native to the soil. train TK23.1 had previously been shown to transiently increase the rate of organic carbon mineralization in soil, via an effect that was recombinant specific and particularly significant in nonsterile soils already possessing an active microflora. he results of this study confirmed the previous findings and showed that additional effects were measurable upon release of the recombinant strain TK23.1 into unamended soil and into soil amended with lignocellulose. n addition to a transient enhancement of carbon mineralization, the recombinant affected soil pH, the rate of incorporation of carbon into soil humus fractions, nitrogen cycling, the relative populations of some microbial groups, and also certain soil enzyme activities. hereas the survival or persistence in soil of both the recombinant TK23.1 strain and its parent, TK23, were similar, the observed effects on microbial numbers, types, and activities were recombinant-specific and did not occur when the parental strain was released into soil. ll of the measured effects were transient, generally lasting for only a few days. hile the effects were statistically significant, their ecological significance appears to be minimal. his is the first report showing that a recombinant actinomycete can affect the microbial ecology of soil in ways that can be readily monitored using a battery of microbiological, enzymological and chemical assays.
