Abstract
Nutritional and physical factors affecting the decomposition of [14C]lignocellulose prepared from Douglas fir (Pseudotsuga menziesii) were examined by incubating the labeled substrate with homogenized surface wood scrapings obtained from a Douglas fir log in a Pacific Northwest stream. Incubations were conducted in distilled water, in stream water collected from four different sources, or in a defined mineral salts solution with or without supplemental N (KNO3). Decomposition rates of [14C]lignocellulose, as measured by 14CO2 evolution, were greater in each of the four filter-sterilized sources of stream water than in distilled water alone. Decomposition experiments conducted in stream water media with the addition of defined mineral salts demonstrated that [14C]cellulose decomposition was stimulated 50% by the addition of either KNO3 or KH2PO4/K2HPO4 and further enhanced (167%) by a combination of both. In contrast, [14C]lignin decomposition was stimulated (65%) only by the addition of both N and P. Decomposition of [14C]lignocellulose was greatest when supplemental KNO3 was supplied in concentrations of at least 10.0 mg of N liter−1 but not increased further by higher concentrations. The decomposition of [14C]lignocellulose increased as the incubation temperature was raised and NO3−1-N supplementation further increased these rates between three-and sevenfold over the range of temperatures examined (5 to 22°C). Accumulation of NH4+ (2 to 4 mg of N liter−1) was always observed in culture filtrates of incubations which had been supplemented with KNO3, the quantity being independent of NO3− concentrations ≥ 10 mg of N liter−1. The role of supplemental NO3− in the decomposition of [14C]lignocellulose is discussed in relation to wood decomposition and the low concentrations of N found in stream ecosystems of the Pacific Northwest.
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Selected References
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- Aumen N. G., Bottomley P. J., Ward G. M., Gregory S. V. Microbial decomposition of wood in streams: distribution of microflora and factors affecting [C]lignocellulose mineralization. Appl Environ Microbiol. 1983 Dec;46(6):1409–1416. doi: 10.1128/aem.46.6.1409-1416.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Barder M. J., Crawford D. L. Effects of carbon and nitrogen supplementation on lignin and cellulose decomposition by a Streptomyces. Can J Microbiol. 1981 Aug;27(8):859–863. doi: 10.1139/m81-136. [DOI] [PubMed] [Google Scholar]
- Federle T. W., Vestal J. R. Lignocellulose mineralization by arctic lake sediments in response to nutrient manipulation. Appl Environ Microbiol. 1980 Jul;40(1):32–39. doi: 10.1128/aem.40.1.32-39.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Keyser P., Kirk T. K., Zeikus J. G. Ligninolytic enzyme system of Phanaerochaete chrysosporium: synthesized in the absence of lignin in response to nitrogen starvation. J Bacteriol. 1978 Sep;135(3):790–797. doi: 10.1128/jb.135.3.790-797.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kingsley M. T., Bohlool B. B. Release of Rhizobium spp. from Tropical Soils and Recovery for Immunofluorescence Enumeration. Appl Environ Microbiol. 1981 Aug;42(2):241–248. doi: 10.1128/aem.42.2.241-248.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]