The previously developed Sphingomonas sp. based optical micro plate biosensor for methyl parathion (MP) was good as it detected multiple samples but had poor stability and low sensitivity. The present study aims to overcome these limitations. Silica nano particles (SiNP) were thus functionalized with polyethyleneimine (PEI) and the functionalized silica nano particles (^fSi NP) were then integrated with Sphingomonas sp. cells. The process was optimized for hydrolysis of MP in top-nitrophenol (PNP). In- tegration of ^fSi NP with cells was confirmed by FT-IR analysis. Biohybrid of Sphingomonas sp.-fSi NP was immobilized on the wells of microplate and associated directly with the optical transducer of microplate reader. Immobilized bio hybrid of Sphingomonas sp.-^fSi NP was characterized using SEM. A detection rangeof0.1–1 ppmMP was achieved from the linear range of calibration plot. After integration with ^fSi NP the storage stability of bio hybrid was enhanced ten times from 18 to 180 days. This study proves that after interaction of cells with ^fSi NP, improved the sensitivity and stability of the bio sensor. Spiked samples were also analyzed and correlated using this bio hybrid based biosensor.