Malolactic bacteria’s proteins mapped

A bacterium that causes malolactic fermentation in wine has been partially genetically mapped by a team of Spanish and Italian scientists.

The report was compiled by a team from university departments in Madrid and Foggia and shows the preliminary map of the 152 proteins that make up a Oenococcus oeni (O. oeni) and dictate the success of malolactic fermentation.

In particular, the researchers were looking at a strain of O. oeni which they called ATCC BAA-1163.

Their findings were revealed at the beginning of the month in the Royal Society’s Open Biology in an essay entitled: “A patial proteme reference map of the wine lactic acid bacterium Oenococcus oeni ATCC BAA-1163.”

O. oeni is the lactic acid bacterium that helps convert malic acid in wine into lactic acid to give the finished product a smoother, less acidic profile.

It is a process to which all red wines are subjected, as are some white wines to a greater of lesser extent.

Industrially produced bacteria is used by most producers but as the authors explain in the introduction of the report: “The harsh wine environment represents a challenge to the survival of O. oeni and can strongly affect the successful outcome of the vinification.

“Therefore, a better understanding of the molecular mechanisms related to the stress adaptation and technical performance of O. oeni is crucial for the characterisation and selection of strains for industrial purposes.”

Having cultivated three different cultures of ATCC BAA-1163, the team were able to detect both the cytoplasmic and membrane proteins in different solutions.

The enzymes used in citrate and malic acid utilisation were also identified, as were four epimerase which are involved “several pathways of carbohydrate metabolism, such as pentose and glucuronate interconversions, galactose, ascorbate and aldarate, starch and sucrose, amino sugar and nucleotide sugar metabolism.”

The entirety of the bacteria has not yet been fully explored (only around 10%) and it was admitted that it had proved impossible to detect the proteins for phenylalanine, tyrosine and tryptophan biosynthesis. The coding genes for ATCC BAA-1163 also remain unidentified.

Nonetheless, the authors noted in their conclusion that, “The analysis allowed the detection of a wide variety of metabolic enzymes, including many involved in the synthesis and catabolism of various carbohydrates, amino acids and amines.

“This study should, therefore, be helpful to those researching the biochemistry of O. oeni ATCC BAA-1163.”

The full study can be read here