Effects of Growth Parameters on the Analysis of Aspergillus flavus Volatile Metabolites

Dongdi Sun,Richard Baird,Julie Gower,Todd Mlsna,Jinyan She,C Stokes,Gary Windham

doi:10.3390/separations3020013

Abstract

Aspergillus flavus produces dangerous secondary metabolites known as aflatoxins, which are toxic and carcinogenic, and their contamination of agricultural products results in health issues and economic hardships in the U.S. and around the world. Early identification of aflatoxigenic isolates of A. flavus is the key in the management of these fungi. An emerging detection method for specific fungi identification involves the analysis of microbial volatile organic compounds (MVOCs) released by the fungi. Complicating this approach is the understanding that many factors influence metabolic production, including growth parameters, such as growth media, temperature, spore counts and oxidation stress. In addition, analytical and data analysis methods can also influence the results. Several growth and analysis methods were evaluated and optimized in order to better understand the effect of the methods on fungi MVOC signatures. The results indicate that carboxen/polydimethylsiloxane (CAR/PDMS) has the best extraction efficiency for the MVOCs emitted by A. flavus. Both chemical defined agar (CDA) and chemical defined liquid (CDL) are suitable growth media for MVOC emission studies. The highest MVOC production was found at 30 °C. Log transformation was considered one of the best data pretreatment methods when analyzing MVOC data and resulted in the best principal component analysis (PCA) clustering in the experiments with different growth media. This study aims to elucidate fungal volatile organic compounds (VOCs) differences due to variations in growth parameters as a first step in the development of an analytical method for the monitoring of aflatoxigenic A. flavus contamination in crop storage facilities.

Highlights

Aflatoxins are secondary metabolic products produced primarily by Aspergillus flavus and Aspergillus parasiticus [1]
This study demonstrates that the experimental parameters used for microbial volatile organic compounds (MVOCs)’ fingerprinting are
This study demonstrates that the experimental parameters used for MVOCs’ fingerprinting are crucial to the outcomes of MVOCs profiles and the data analysis

Summary

Introduction

Aflatoxins are secondary metabolic products produced primarily by Aspergillus flavus and Aspergillus parasiticus [1]. Peanut and other agricultural commodities has a significant impact on health and the agricultural economy, especially in the southeastern. United States, where aflatoxin contamination costs farmers, buyers and sellers an annual average of. The production of aflatoxins is always associated with the production of other metabolites, some of which are volatile. These volatile metabolites are produced during both primary and secondary metabolism and are often collectively referred to as microbial volatile organic compounds (MVOCs) [3]. MVOCs are widely investigated as the indicator of fungal growth [4,5,6,7], mycotoxins’ production [8,9,10] and for fungal taxonomy [11,12,13].

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Conclusion