High-throughput screening of Mucoromycota fungi for production of low- and high-value lipids

Gergely Kosa,Achim Kohler,Nils Kristian Afseth,Boris Zimmermann,Dag Ekeberg,Jerome Mounier,Volha Shapaval

doi:10.1186/s13068-018-1070-7

Gergely Kosa, Achim Kohler + Show 5 more

Open Access

https://doi.org/10.1186/s13068-018-1070-7

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Abstract

BackgroundMucoromycota fungi are important producers of low- and high-value lipids. Mortierella alpina is used for arachidonic acid production at industrial scale. In addition, oleaginous Mucoromycota fungi are promising candidates for biodiesel production. A critical step in the development of such biotechnological applications is the selection of suitable strains for lipid production. The aim of the present study was to use the Duetz-microtiter plate system combined with Fourier transform infrared (FTIR) spectroscopy for high-throughput screening of the potential of 100 Mucoromycota strains to produce low- and high-value lipids.ResultsWith this reproducible, high-throughput method, we found several promising strains for high-value omega-6 polyunsaturated fatty acid (PUFA) and biodiesel production purposes. Gamma-linolenic acid content was the highest in Mucor fragilis UBOCC-A-109196 (24.5% of total fatty acids), and Cunninghamella echinulata VKM F-470 (24.0%). For the first time, we observed concomitant gamma-linolenic acid and alpha-linolenic acid (up to 13.0%) production in psychrophilic Mucor flavus strains. Arachidonic acid was present the highest amount in M. alpina ATCC 32222 (41.1% of total fatty acids). Low cultivation temperature (15 °C) activated the temperature sensitive ∆17 desaturase enzyme in Mortierella spp., resulting in eicosapentaenoic acid production with up to 11.0% of total fatty acids in M. humilis VKM F-1494. Cunninghamella blakesleeana CCM-705, Umbelopsis vinacea CCM F-539 and UBOCC-A-101347 showed very good growth (23–26 g/L) and lipid production (7.0–8.3 g/L) with high palmitic and oleic acid, and low PUFA content, which makes them attractive candidates for biodiesel production. Absidia glauca CCM 451 had the highest total lipid content (47.2% of biomass) of all tested strains. We also demonstrated the potential of FTIR spectroscopy for high-throughput screening of total lipid content of oleaginous fungi.ConclusionsThe use of Duetz-microtiter plate system combined with FTIR spectroscopy and multivariate analysis, is a feasible approach for high-throughput screening of lipid production in Mucoromycota fungi. Several promising strains have been identified by this method for the production of high-value PUFA and biodiesel.

Highlights

Mucoromycota fungi are important producers of low- and high-value lipids
Most of the fungal biomass had a white color with the exception of some Mucor strains which had pale yellow (M. circinelloides FRR 5020, FRR 5021, FRR 4846, M. mucedo Université de Bretagne Occidentale Culture Collection (UBOCC)-A-101361), intense yellow (M. hiemalis UBOCC-A-101359, 101360, 111119, 112185) or dark green color (M. mucedo UBOCC-A-101353, 101362), due to the production of carotenoids and other pigments (Fig. 1c, d)
This study showed that the Duetz-MTPS is suitable for the reproducible cultivation of a large variety of Mucoromycota fungi, while revealing details about their lipid production potential

Summary

Introduction

Mucoromycota fungi are important producers of low- and high-value lipids. Mortierella alpina is used for arachidonic acid production at industrial scale. Oleaginous microorganisms have been considered for nearly a century as an alternative source for the production of low- and high-value lipids (i.e. single cell oils) It is only in the past two or three decades they have been used commercially [1]. Oil of microalgae and filamentous fungi are good sources of high value omega-3 and omega-6 long-chain polyunsaturated fatty acids, respectively These PUFAs include eicosapentaenoic acid, (EPA, C20:5n3), docosahexaenoic acid (DHA, C22:6n3), γ-linolenic acid (GLA, C18:3n6), dihomo-γlinolenic acid (DGLA, C20:3n6) and arachidonic acid (ARA, C20:4n6). Microbial lipids (yeasts, filamentous fungi and microalgae) have been considered as possible alternative source for biodiesel production, since they can potentially contain high amounts of saturated (SAT) and monounsaturated fatty acids (MUFA) and can grow rapidly in a controlled environment. Fungi (yeast and molds) are able to grow and accumulate lipids on such substrates [8,9,10,11]

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