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Genetic Engineering of an Unconventional Yeast for Renewable Biofuel and Biochemical Production
Published on: September 20, 2016
Lipase production by yeasts from extra virgin olive oil
G Ciafardini1, B A Zullo, A Iride
1Department of Animal, Plant and Environmental Sciences, Agriculture Faculty, Molise University, Via De Sanctis, I-86100 Campobasso, Italy. ciafardi@unimol.it
Food Microbiology
|September 1, 2006
Summary
Lipase-producing yeasts found in extra virgin olive oil can degrade oil quality by hydrolyzing triglycerides. This study identifies specific yeast strains and their activity, impacting olive oil
Area of Science:
- Microbiology
- Food Science
- Biochemistry
Background:
- Newly produced olive oil contains suspended particles and water, hosting micro-flora.
- Previous research indicated beneficial micro-flora in olive oil hydrolyzing oleuropein.
- The role of yeasts in olive oil quality, specifically triglyceride hydrolysis, was unexplored.
Purpose of the Study:
- To investigate the presence and impact of lipase-producing yeasts in extra virgin olive oil.
- To identify specific yeast strains capable of hydrolyzing olive oil triglycerides.
- To understand the factors influencing yeast lipase activity in olive oil.
Main Methods:
- Microbiological analysis of extra virgin olive oil samples.
- Enzymatic assays using synthetic substrates and olive oil triglycerides.
- Testing lipase activity of isolated yeast strains (Saccharomyces cerevisiae 1525, Williopsis californica 1639).
- Investigating the effect of aqueous to organic phase ratio and free fatty acids on enzyme activity.
Main Results:
- Lipase-positive yeasts were identified in extra virgin olive oil samples.
- Saccharomyces cerevisiae 1525 and Williopsis californica 1639 demonstrated lipase activity on various substrates, including olive oil triglycerides.
- Lipase activity varied between whole cells and extracellular fractions, influenced by water content and free fatty acids.
- The prevalence of lipase-producing yeasts ranged from 0% to 56% in commercial olive oils from different regions.
Conclusions:
- Lipase-producing yeasts can negatively impact extra virgin olive oil quality through triglyceride hydrolysis.
- The presence and activity of these yeasts are influenced by environmental factors within the oil.
- Yeasts represent a significant factor in both positive and negative organological changes in olive oil.
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