Two commoly exploited fungal species are Saccharomyces cerevisiae and Streptococcus thermophilus.
Saccharomyces cerevisiae is used mainly on bread industry. As yeast, these fungi are very active metabolically. They ferment the cereal's sugars producing CO2 taht makes the bread rise.
Streptococcus thermophilus are used for yogurts. These also ferment sugar, this time lactose (milk's sugar), creating acid lactic that confers to the yogurt its acid taste and gives it the more solid texture.