Culture-independent methods of microbial identification have been developed, which allow for DNA extraction directly from environmental samples without subjecting microbes to growth on nutrient media. These methods often involve next generation DNA sequencing (NGS) for identifying microbes and qPCR for quantifying them. Despite the benefits of extracting all DNA from the sample, results may be compromised by amplifying DNA from dead cells.
In a recent study, researchers of the University of British Columbia developed a technique that combines a process to identify the full spectrum of DNA in yeast and bacteria samples with a technique that distinguishes between live and dead micro-organisms. Key in the development of their method was the use of a light-sensitive dye, propidium monoazide, which deactivates DNA in non-viable cells and thereby prevents it from being detected. The colleagues tried to identifying the yeast and bacterial diversity of wines.
Since only live micro-organisms are relevant in the various stages of fermentation as they relate to the senses, this study provides some of the important tools that will be necessary to determine why different types of wine taste and smell as they do. While more research needs to be conducted, these findings could also lead to the identification and elimination of micro-organisms that are responsible for spoilage.
The new technique allows for a much faster and more accurate assessment. What previously could have taken multiple experiments and months of trial and error, can now be done in a single experiment.
The next stages of research will focus this technique on different types of wine making methods to see how they change micro-organisms that affect the final wine product.