Biopreservation includes: keeping animals/plants alive and fermentation.
A well known type of fermentation is vinification. In this progress, sugars are converted into ethanol using yeast. Any sugar rich juice will ferment naturally, or you can add your own yeast to speed the process along. Malt sugars are used to make beer, fruit sugars are used to make wines. Mead is fermented honey.
Unfortunately, the byproduct of yeast, alcohol, will become toxic at certain levels. Some yeasts are more tolerant of higher alcohol levels than others, champaign yeast will survive even at 15% alcohol. After the yeast has died, the product may be distilled to raise the alcohol level even further.
Another practical fermentation method is lacto-fermentation or lactic acid fermentation. This type of fermentation occurs when certain bacteria, commonly from genus Lactobacillus, are grown in food. Typically, the growth of the bacteria raises the pH of the food, creating an environment that is hostile to various spoilage-causing bacteria. Common foods preserved with this method are yogurt, sauerkraut, pickles, and kimchi, though many other types of foods can be cultured in this way. Lacto-fermentation is practical for short-term food storage in a home kitchen.