Dictionary

ALGAE:

Algae have no stem, root, leaf or flower and are capable of photosynthesis. They are plants living mainly in an aquatic environment.

BACTERICIDE:

A substance with the ability to kill bacteria.

BACTERIUM:

A microorganism consisting of a single cell, without a nucleus, with a very simple structure, considered to be neither animal nor plant.

BIOFUEL:

A biofuel is a fuel produced from non-fossil organic materials. These fuels are more sensitive to micro-organisms than fossil fuels.

BIODEGRADATION :

Biodegradation is the decomposition of organic matter by micro-organisms such as bacteria, fungi or algae. This degradation is desired, unlike biodeterioration.

BIODETERIORATION :

Biodeterioration can be defined as an undesired change in the properties of a material induced by the presence and activity of organisms (macro and micro), and the processes by which these living organisms alter these properties and the value of these materials.

Biodeterioration can be:

aesthetic (coloured stains and dirt)
physical and mechanical: alteration of structures due to movement and growth of bacteria
chemical: either by using the components of the structure as a source of carbon and nutrients, or by degrading thanks to the production of aggressive molecules by micro-organisms.

BIOCIDE :

The term biocide is composed of the prefix "bio-" from the ancient Greek bios meaning life and the suffix "-cide" from the Latin caedo which expresses the idea of killing. Regulation (EU) 528/2012 of 22 May 2012 on the placing on the market and use of biocidal products defines biocidal products as any substance or mixture intended to destroy, repel, render harmless, prevent the action of, or control harmful organisms.

BIOFILM :

It is a multicellular assembly of different microorganisms that adhere to a surface and to each other while secreting a protective and adhesive matrix. The best known example is dental plaque.

BIOMINERALIZATION :

Biomineralization is the use of the ability of certain telluric micro-organisms to produce calcium carbonate on the surface of the stone. The biocalcin thus formed lines the surface microporosities of the stone. This treatment reduces water penetration without modifying gas exchanges.

BIOSURFACTANT:

Microorganisms use a variety of organic compounds as a source of carbon and energy for their growth. When the carbon source is insoluble like a hydrocarbon, microorganisms facilitate their diffusion into the cell by producing a variety of substances: biosurfactants. Biosurfactants are complex molecules covering a wide range of chemical products including peptides, fatty acids, phospholipids, glycolipids, antibiotics, lipopeptides, etc.

JET FUEL :

There are basically three types of jet fuels:

The jet fuel used by international civil aviation is Jet A1 kerosene. The military uses this fuel but with an anti-ice additive.

Military navies use high-flashpoint kerosene, heavier than Jet A1, on their ships for on-board aircraft to store it safely in the cargo holds.

Wide cut jet fuel, with a very low initial distillation point obtained by mixing naphtha and kerosene, reserved almost exclusively for military applications.

DISINFECTION:

Disinfection is an operation with a momentary result, which makes it possible to eliminate or kill micro-organisms and to inactivate the undesirable viruses carried by the contaminated inert media according to the fixed objectives. The result of this operation is limited to the micro-organisms present at the time of the operation.
By definition, a disinfection aims to reduce a population of microorganisms, but not necessarily to eliminate it entirely. According to the AFNOR NF EN 14885 standard (November 2018), a disinfectant must achieve a reduction of 5 log bacterial inoculum, 4 log fungal inoculum, 4 log viral inoculum and 5 log spore inoculum. After disinfection, an object can still be a carrier of microorganisms if it is highly contaminated to begin with.

MIDDLE DISTILLATES :

Middle distillates are derived from the atmospheric distillation of crude oil. Middle distillates include kerosene, gas oil and heating oil.

Distillation fractions	Boiling temperature (t)	Formula	Use
Gas	t < 20°C	C₃H₈, CH₄, C₂H₆, C₄H₁₀	Same compounds as natural gas
Gasoline	20°C < t < 150°C	Cut C₅ - C₁₀	Regular gasoline Light fractions: petroleum ether Heavy fractions: solvents
Middle distillates : Kerosene or paraffin oil	180°C < t < 230°C	Cut C₁₁- C₁₂	Jet engine fuels
Middle distillates : Diesel	230°C < t < 300°C	Cut C₁₃ - C₁₇	Diesel engine fuels and heating
Middle distillates : Domestic fuel oil	300°C < t < 400°C	Cut C₁₈ - C₂₅	Heating
Lubricants	400°C < t < 500°C	Cut C₂₆ - C₃₈	Lubrication, cracking →lighter fractions
Heavy fuel oil	t >500°C		Fuel oil (heating), catalytic cracking→ lighter fractions
Asphalt			Paving, road surfacing

FUNGICIDE:

A fungicide is a substance designed to eliminate or limit (fungistatic) fungal growth.

HUMIDITY:

Definition of 2 different humidity concepts:

The Aw (Activity of water) defines the amount of reactive water in a substrate, therefore available, for a given temperature. The scale of the activity of water in a substrate varies from 1 to 0.

Relative humidity (RH) is the ratio expressed as a percentage between the partial pressure of water vapour actually contained in a given volume of air and the maximum partial pressure of water vapour that this volume could contain at the same température :

All substrates are in equilibrium with the surrounding relative humidity (RH) and a corresponding water activity (Aw). At low values this water is very strongly bound to the macromolecules and is not available for micro organisms.

Not all microorganisms behave in the same way with regard to the humidity factor. The most demanding in terms of available water are undoubtedly bacteria. When the quantity of water available is sufficient, they will have an explosive growth and the product will be degraded in a few days or even hours. On the " biens culturels ", the risk of saprophytic alteration alone is extremely low in our climates, unless there is a very serious accident such as a major water leak.

The micro-organisms that require the least water are moulds. These microscopic fungi constitute a very heterogeneous group in terms of their requirements for the hydration factor.

KEROSENE:

Kerosene is a medium refinery cut, intermediate between gasoline and diesel that can have several uses: heating, lighting, aircraft propulsion and land turbines.

LICHEN:

Plant resulting from the association of an algae and a fungus.

MICROBICIDE:

Substance with the ability to kill microorganisms.

MOISTURE:

Moulds are microscopic fungi that grow when exposed to moisture.

MOSS:

Plant shaves wet areas forming spongy mats composed of several organisms.

CLEANING :

Cleaning is the essential preliminary step to sterilization or disinfection. The objective is to eliminate organic matter and germs present. The state of cleanliness obtained conditions the quality of the subsequent sterilization or disinfection.

STERILIZATION:

Sterilization is an operation that eliminates or kills micro-organisms carried by contaminated inert media, the result of which is a 0 degree at the end of the operation and which allows this state to be maintained for a specified period of time.
After sterilization, unlike disinfection, the survival of micro-organisms is highly unlikely and the packaging allows the sterility to be maintained for some time.
When sterilization is properly conducted, the theoretical probability of a viable microorganism being present on a device should be 1 to 1 million. In other words, no more than one contaminated item in a million should be found.

SULPHATE-REDUCING BACTERIA :

Anaerobic bacteria capable of reducing sulphates to sulphide ions.

VIRUCIDE:

Substance having the ability to kill viruses

VIRUS:

An infectious agent requiring a host, often a cell whose metabolism and constituents it uses to replicate.