The FT-IR spectroscopic analysis of microorganisms allows a fast and reliable identification of microorganisms at low running expenses.

Due to the large variety of analytical questions and the high number of different microorganism species many analytical methods are applied in microbiology. The differentiation of microorganisms by morphological characteristics and their identification using biochemical staining tests are typically applied techniques. In recent years more and more molecular biological methods have been used. Apart from the identification of the microorganism medical applications require the determination of its pathogenity and resistance against antibiotics. In biotechnology monitoring of the production of certain natural materials or recombinant proteins is of interest.

FT-IR spectroscopy is a method that combines high sensitivity with a broad field of applications. Using FT-IR spectroscopy biomolecules like proteins, lipids, carbohydrates and DNA/RNA can be identified and quantified very sensitively. When cultivating microorganisms under standardized conditions a characteristic pattern of these biomolecules is obtained, allowing a reliable identification of the strain.

Sample preparation is quick and easy: The microorganisms are harvested from the cultivation medium, suspended in water and then transferred on a special IR-transparent, reusable sample plate. The measurement is performed after drying of the samples. The IR-method allows in-depth differentiation, often down to strain level and furthermore it can be used for additional examinations, e.g. to monitor the production of certain metabolites.

As no complex media or chemicals are required the method is characterized by low running costs and allows reducing waste. Bruker offers dedicated systems for microbiological applications like the microplate module HTS-XT that is designed for high sample throughput. Analysis is performed with the user friendly  OPUS/LAB software that is designed for easy analysis of large sample numbers. This software was developed considering the standards for quality control in the pharmaceutical industry (GLP, CFR 21 Part 11).

Method characteristics

• Quick and reliable results
• Identification down to strain level possible
• Applicable for bacteria, yeast and fungi
• Automated measurement, data control and evaluation
• High sample throughput
• Low running costs (reusable sample plates: no disposables)
• Less waste and disposal costs
• Easy and fast sample preparation
• Library set-up and modification by user possible

Users

• Pharmaceutical industry (clean room monitoring)
• Food industry
• Strain collections
• Environmental microbiology
• Biotechnology

Applications

• Identification of microorganisms
• Classification of microorganisms
• In-depth differentiation
• Fermentation control
• Examination of metabolites
• Study of antibiotics

Data bases

Data bases for microorganism identification were created and validated at the Institute for Microbiology of the Zentralinstitut für Ernährungs- und Lebensmittelforschung Weihenstephan in the group of Prof. Dr. Siegfried Scherer. There are data bases available for the following groups of microorganisms:

• Yeast
• Coryneforms
• Bacilli
• Micrococci, Staphylococci
• Bifido bacteria, Clostridia
• Pseudomonads
• Lactobacilli and Lactococci
• Acetobactereaceae