Due to the presence of organic and inorganic nutrients in water circuits, water processes represent ideal media for growth of microorganisms. These microorganisms form biofilms that affect equipment and the quality of final products. This biofouling can be removed by performing an enzymatic treatment or using a bio filtrating device. VIT kits allow monitoring of the formation of biofilms. In the same way, the formation of foam in many activated sludge treatment and recovering plants are caused by filamentous bacteria. These microorganisms cannot be detected with traditional sensing tools but the VIT system is particularly suitable for detecting and monitoring such bacteria.
The core element of the VIT system is a gene probe. This probe is capable of linking itself to the specific genetic signature of bacteria. In this way, it fits like a key to a lock. Gene probes are small pieces of DNA which are labelled with a fluorescent dye. When gene probes are introduced into the bacteria, they search for targets within the bacteria (i.e. the so-called specific genetic signatures). Once these targets have been found, the probe binds to them together with the fluorescent dye. Depending on the labelling of the gene probe, the bacteria will shine in different colours when it will be submitted to a fluorescence microscope analysis. As the genetic code is either specific for a single species or for a whole bacteria group, the gene probes can be designed to carry out a global analysis and/or to go down to species.
The VIT toolkit consists of three components that are (i) a set of solutions required for the genes probes to bind only the bacteria they are designed for, (ii) the gene probe itself and (iii) the VIT-reactor to carry out the incubation properly. The entire procedure requires up to three hours and can be performed by everyone. The major added value of the VIT system is that it investigates the bacteria directly in the sample, in opposition to conventional analysis, where bacteria grow on artificial media. In conventional analyses, bacteria are transferred from their initial source on artificial media where they grow to colonies which are then analysed. It is a slow and sometimes inaccurate and inadequate method, especially when non cultivable bacteria are sought. On the contrary, the VIT technique is specific (accurate and precise), fast (detection of micro-organisms within hours) and reliable (based upon huge databases).
VIT kits can be used in various industrial sectors such as wastewater treatment, medical laboratories, dairy products, food and drink products and cosmetics and pharmaceutics where good manufacturing practices are required. Manifold VIT kits are already available for example for identifying Legionella, Pseudomas aeruginosa, beer spoiling bacteria, Salmonella, Listeria or Escherichia coli. Consequently, the Technology Readiness Level is estimated to be 9 on the TRL scale.
Within the AQUAFIT4USE project, VIT kits were developed and used to detect specific bacteria that are of particular concern for paper mill sludge disposal and recovering. The AQUAFIT4USE project, financed under the 7th Framework Programme (FP7), a grant funding programme of the European Commission. It aims to make industries more independent of the supply of water for their production processes. The initiative aims to develop new technologies, tools and methods for sustainable water supply, use and discharge in the main water consuming industries: in other words “water fit-for-(re)use”. These new techniques encompass innovative technologies or applied technologies dealing with water looping in the paper industry but also in the food, chemistry and textile industries.