Application of an Escherichia coli green fluorescent protein-based lysine biosensor under nonsterile conditions and autofluorescence background.
OBJECTIVE
To examine the utility of an Escherichia coli green fluorescent protein (GFP) containing biosensor for quantification of bioavailable lysine in selected feed samples under nonsterile conditions and to estimate the background fluorescence of analyzed feed samples and evaluate the risk of confounding GFP emission from the lysine assay organism.


RESULTS
Escherichia coli lysine auxotroph GFP based biosensor was used to determine the percentage of bioavailable lysine in two samples of soybean-, cottonseed-, and meat and bone meal under nonsterile conditions. The fluorescence emitted by GFP was successfully measured using a spectrofluorimeter to monitor bacterial growth response to protein-derived lysine and lysine containing small peptides. The autofluorescence of analyzed feed samples at different concentrations could also be estimated.


CONCLUSIONS
When feed protein concentrations are decreased, autofluorescence interference can be avoided.


CONCLUSIONS
The E. coli lysine auxotroph GFP-based biosensor can successfully be used for the determination of bioavailable lysine in these selected animal feed proteins under nonsterile conditions.


CONCLUSIONS
E. coli GFP biosensor for lysine has potential for routine application in animal feeds.
Chalova
V
V
Department of Poultry Science, Texas A and M University, College Station, TX 77843, USA.
Woodward
C L
CL
Ricke
S C
SC
D000821:Animal Feed / Q000032:analysis*; D001688:Biological Products; D015374:Biosensing Techniques / Q000379:methods*; D003369:Cottonseed Oil / Q000032:analysis / Q000737:chemistry; D048168:Escherichia coli K12; D029968:Escherichia coli Proteins; D049452:Green Fluorescent Proteins; D008460:Meat / Q000032:analysis; D008903:Minerals / Q000032:analysis / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry
D001688:Biological Products; D003369:Cottonseed Oil; D029968:Escherichia coli Proteins; D008903:Minerals; D049452:Green Fluorescent Proteins; C027762:bone meal