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Comparison of Phosphorus Forms in Wet and Dried Animal Manures by Solution Phosphorus‐31 Nuclear Magnetic Resonance Spectroscopy and Enzymatic Hydrolysis
Author(s) -
He Zhongqi,
CadeMenun Barbara J.,
Toor Gurpal S.,
Fortuna AnnMarie,
Honeycutt C. Wayne,
Sims J. Thomas
Publication year - 2007
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2006.0549
Subject(s) - hydrolysis , chemistry , manure , phosphomonoesters , phosphorus , enzymatic hydrolysis , nuclear magnetic resonance spectroscopy , phytase , phytic acid , enzyme , food science , agronomy , biochemistry , organic chemistry , biology , inorganic phosphate
Both enzymatic hydrolysis and solution 31 P nuclear magnetic resonance (NMR) spectroscopy have been used to characterize P compounds in animal manures. In this study, we comparatively investigated P forms in 0.25 M NaOH/0.05 M EDTA extracts of dairy and poultry manures by the two methods. For the dairy manure, enzymatic hydrolysis revealed that the majority of extracted P was inorganic P (56%), with 10% phytate‐like P, 9% simple monoester P, 6% polynucleotide‐like P, and 18% non‐hydrolyzable P. Similar results were obtained by NMR spectroscopy, which showed that inorganic P was the major P fraction (64–73%), followed by 6% phytic acid, 14 to 22% other monoesters, and 7% phosphodiesters. In the poultry manure, enzymatic hydrolysis showed that inorganic P was the largest fraction (71%), followed by 15% phytate‐like P and 1% other monoesters, and 3% polynucleotide‐like P. NMR spectroscopy revealed that orthophosphate was 51 to 63% of extracted P, phytic acid 24 to 33%, other phosphomonoesters 6 to 12%, and phospholipids and DNA 2% each. Drying process increased orthophosphate (8.4% of total P) in dairy manure, but decreased orthophosphate (13.3% of total P) in poultry manure, suggesting that drying treatment caused the hydrolysis of some organic P to orthophosphate in dairy manure, but less recovery of orthophosphate in poultry manure. Comparison of these data indicates that the distribution patterns of major P forms in animal manure determined by the two methods were similar. Researchers can utilize the method that best fits their specific research goals or use both methods to obtain a full spectrum of manure P characterization.