Vegetable oils as carbon and energy source for Aureobasidium melanogenum in batch cultivation.

Elke J Van Nieuwenhuijzen,Robert A Samson,Olaf C G Adan,Michael F Sailer,Stephanie Rensink,Edwin R Van Den Heuvel

doi:10.1002/mbo3.764

Elke J Van Nieuwenhuijzen, Robert A Samson + Show 4 more

Open Access

https://doi.org/10.1002/mbo3.764

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Abstract

Dark homogenous fungal‐based layers called biofinishes and vegetable oils are key ingredients of an innovative wood protecting system. The aim of this study was to determine which of the vegetable oils that have been used to generate biofinishes on wood will provide carbon and energy for the biofinish‐inhabiting fungus Aureobasidium melanogenum, and to determine the effect of the oil type and the amount of oil on the cell yield. Aureobasidium melanogenum was cultivated in shake flasks with different types and amounts of carbon‐based nutrients. Oil‐related total cell and colony‐forming unit growth were demonstrated in suspensions with initially 1% raw linseed, stand linseed, and olive oil. Oil‐related cell growth was also demonstrated with raw linseed oil, using an initial amount of 0.02% and an oil addition during cultivation. Nile red staining showed the accumulation of fatty acids inside cells grown in the presence of oil. In conclusion, each tested vegetable oil was used as carbon and energy source by A. melanogenum. The results indicated that stand linseed oil provides less carbon and energy than olive and raw linseed oil. This research is a fundamental step in unraveling the effects of vegetable oils on biofinish formation.

Highlights

The measurements performed on the suspensions with an initial amount of 1% oil and a second oil supply of 1% during incubation showed an increase in total cell and colony‐forming unit (CFU) concentration in the first few days of incubation (Figures 3 and 4)
For exam‐ ple, the raw linseed oil suspension of shake flask cultivation (set A) showed a drop of CFU concentration at day 8, which significantly differed from the other data points (Figure 2)
The stand linseed oil suspension showed a lower median CFU concentration at day 5 than at day 2 (Figure 4), while the corresponding total cell counts had a similar concentration at these two time points (Figure 3)

Summary

Introduction

The counting chamber measurements performed on the suspensions with 1% vegetable oil showed an increase in total cell concentration in the first few days of incubation (Figure 1). The measurements performed on the suspensions with an initial amount of 1% oil and a second oil supply of 1% during incubation showed an increase in total cell and CFU concentration in the first few days of incubation (Figures 3 and 4).

Objectives

Results

Conclusion