Detection of Penicillin G Produced by Penicillium chrysogenum KF 425 in Vivo with Raman Microspectroscopy and Multivariate Curve Resolution-Alternating Least Squares Methods

Abstract

Raman microspectroscopy is a minimally invasive technique that can identify molecular structure without labeling. In this study, we demonstrate in vivo detection of the bioactive compound penicillin G inside Penicillium chrysogenum KF425 fungus cells. Highly overlapped spectroscopic signatures acquired using Raman microspectroscopic imaging are analyzed using a multivariate curve resolution-alternating least squares (MCR-ALS) method to extract the pure spectra of individual molecular constituents. In addition to detecting multiple constituents such as proteins and lipids, we observe the subcellular localization of penicillin G like granule particle inside the fungus body. To date, there have been no reports of direct visualization of intracellular localization of penicillin G. The methodology we present in this article is expected to be applied as a screening tool for the production of bioactive compounds by microorganisms.