Acetic acid bacteria Acetic acid bacteria belong to the family Acetobacteriaceae, commonly known as vinegar bacteria, and are often responsible for the vinegary spoilage of wines through the production of acetaldehyde and acetic acid from ethanol (and glucose).

1. A gelatinous material, an extract from red algae (mainly Gelidium and Gracilaria species), used as a base for bacterial culture media and as a stabilizer and thickener in many food products.
2. A culture medium containing this material.

Apiculate Terminating in a short, sharp, flexible point.

Asexual Not forming part of a cycle which involves fertilisation and meiosis.

Asexual reproduction Reproduction in which an organism produces one or more clones of itself, such as by fission or budding.

Bacteria Tiny, unicellular, prokaryotic organisms that reproduce by cell division and usually have cell walls; can be shaped like spheres, rods or spirals and can be found in virtually any environment.

Budding Asexual reproduction (usually in yeasts) beginning as a protuberance from the parent cell that grows to become a daughter cell.

Coccoid Sphere-shaped.

Coccus, pl cocci A bacterium with a rounded or spherical shape.

Diplococcus A pair of cocci.

Diploid A full set of genetic material, consisting of paired chromosomes.

Eukaryote A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus.

Fermentative Capable of performing fermentation.

Fermentation The chemical decomposition of a substance, usually a carbohydrate, due to the action of enzymes produced by bacteria, yeasts or moulds. Fermentation usually occurs in an oxygen-free environment, and typically involves the conversion of starch or sugar into ethanol.

Fission budding A type of cell division in which overall (i.e. not localised) cell growth is followed by septum formation which typically divides the fully grown cell into two similar or identical cells.

Fungus Any of numerous eukaryotic organisms of the kingdom Fungi, which lack chlorophyll and vascular tissue and range in form from a single cell to a body mass of branched filamentous hyphae that often produce specialized fruiting bodies. The kingdom includes the yeasts, moulds, smuts, and mushrooms.

Genus – plural Genera The second most specific taxonomic level; includes closely related species. Interbreeding between organisms within the same genus can occur.

Haploid A single set of chromosomes (half the full set of genetic material), present in the egg and sperm cells of animals and in the egg and pollen cells of plants.

Hyphae Any of the threadlike filaments forming the mycelium of a fungus.

Inoculating loop A small loop of wire on a handle that is used to transfer microbiological samples, aseptically.

Inoculum Material used to initiate a microbial culture.

Killer yeast A yeast that secretes a toxin that can kill other yeasts.

Lactic acid bacteria Those bacteria which can produce lactic acid from the fermentation of glucose.

Lenticular Shaped like a biconvex lens: ().

Malo-lactic fermentation (MLF) The conversion of malic acid to lactic acid and carbon dioxide, carried out by some of the lactic acid bacteria.

Meiosis The process of cell division in sexually reproducing organisms that reduces the number of chromosomes in reproductive cells from diploid to haploid, leading to the production of gametes in animals and spores in plants.

Mould A filamentous fungus.

Mycelium The diffuse, indefinite body of a multicellular fungus, which is composed of many fine, branching tubes called hyphae.

Oenococcus oeni Formerly known as Leuconostoc oenos, the bacteria most often responsible for malolactic fermentation in winemaking.

Ogival A pointed arch.

Phylum A primary division of a kingdom, as of the animal kingdom, ranking next above a class in size.

Prokaryote a unicellular organism having cells lacking membrane-bound nuclei; bacteria are the prime example but also included are blue-green algae and actinomycetes and mycoplasma.

Saccharomyces cerevisiae The yeast most commonly responsible for alcoholic fermentation in winemaking.

Sexual reproduction The process where two cells (gametes) fuse to form one hybrid, fertilised cell; resulting in a new genome that is different from that of either parent.

Spore A small, usually single-celled reproductive body that is highly resistant to desiccation and heat and is capable of growing into a new organism, produced especially by certain bacteria, fungi, algae, and non-flowering plants.

Sporulating Spore-forming.

Strain A group of organisms of the same species, having distinctive characteristics but not usually considered a separate breed or variety.

Taxonomy The classification of organisms in an ordered system that indicates natural relationships. The taxonomic organisation of species is hierarchical. Each species belongs to a genus, each genus belongs to a family, and so on through order, class, phylum, and kingdom. Associations within the hierarchy reflect evolutionary relationships, which are deduced typically from morphological and physiological similarities between species. So, for example, species in the same genus are more closely related and more alike than species that are in different genera within the same family. Carolus Linnaeus, an 18th-century Swedish botanist, devised the system of binomial nomenclature used for naming species. In this system, each species is given a two-part Latin name, formed by appending a specific epithet to the genus name. By convention, the genus name is capitalised, and both the genus name and specific epithet are italicised, for example Oenococcus oeni.

Tetrad A group of four.

Yeast Any of many small, single-celled fungi in the phylum Ascomycota that reproduce by budding; the yeasts used to produce alcohol through fermentation or to leaven bread are all in the genus Saccharomyces.