Biotransformation of Animal Fat-By Products into ARA-Enriched Fermented Bioproducts by Solid-State Fermentation of Mortierella alpina

Abstract

Solid-state fermentation (SSF) is a powerful fermentation technology for valorizing rest materials and by-products of different origin. Oleaginous Zygomycetes fungi are often used in SSF as an effective cell factory able to valorize a wide range of hydrophilic and hydrophobic substrates and produce lipid-enriched bioproducts. In this study, for the first time, the strain Mortierella alpina was used in SSF for the bioconversion of animal fat by-products into high value fermented bioproducts enriched with arachidonic acid (ARA). Two cereals-based matrixes mixed with four different concentrations of animal fat by-product were evaluated for finding optimal conditions of a fat-based SSF. All obtained fermented bioproducts were found to be enriched with ARA. The highest substrate utilization (25.8%) was reached for cornmeal and it was almost double than for the respective wheat bran samples. Similarly, total fatty acid content in a fermented bioproduct prepared on cornmeal is almost four times higher in contrast to wheat bran-based bioproduct. Although in general the addition of an animal fat by-product caused a gradual cessation of ARA yield in the obtained fermented bioproduct, the content of ARA in fungal biomass was higher. Thus, M. alpina CCF2861 effectively transformed exogenous fatty acids from animal fat substrate to ARA. Maximum yield of 32.1 mg of ARA/g of bioproduct was reached when using cornmeal mixed with 5% (w/w) of an animal fat by-product as substrate. Furthermore, implementation of attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy in characterization of obtained SSF bioproducts was successfully tested as an alternative tool for complex analysis, compared to traditional time-consuming methods.

Animal Fat as a Substrate for Production of n-6 Fatty Acids by Fungal Solid-State Fermentation

“…Furthermore, the study also describes the increased antioxidant activity of these bioproducts. Moreover, a novel approach of analysis of SSF bioproducts using Fourier transform infrared (FTIR) spectroscopy reported recently [ 13 ] as an alternative method for the accurate monitoring of SSF processes was also confirmed.…”

“…Both cereal substrates were processed according to the method described by Slaný et al [ 13 ]. The composition of cereal substrates mixtures with Tween ® 40 and animal fat is summarized in Table 2 .…”

“…Animal fat emulsions were prepared by mixing distilled water, Tween ® 40, and animal fat material using a combination of heating, stirring, and sonication by VWR USC300T ultrasonic homogenizer (VWR International, Radnor, PA, USA) according to Slaný et al [ 13 ].…”

“…A specific fermentation process called solid-state fermentation (SSF) is a well-described process using a solid matrix and almost no water, accompanied by a high-production capacity [ 11 , 12 ]. Application of SSF with Zygomycetes fungi as a main production cell factories allow acquiring of bioproducts enriched with various long-chain unsaturated fatty acids [ 6 , 13 , 14 ] and also other specific valuable products, such as glucosamine [ 15 ], carotenoid pigments [ 6 , 16 , 17 , 18 ], coenzymes [ 19 ], etc. Furthermore, the process of SSF often leads to the increased enzyme activity (e.g.…”

“…However, all of these biotransformation processes are performed under the condition of the submerged fermentation. Our team pioneered and described the process of SSF using solid animal fat by-product substrates [ 13 ]. Using Zygomycetes strain Mortierella alpina CCF2861, bioproducts with the increased level of ω-6 fatty acids was obtained.…”