Submerged Fermentation of Animal Fat By-Products by Oleaginous Filamentous Fungi for the Production of Unsaturated Single Cell Oil

Animal waste fats were explored as a fermentation substrate for the production of high-value unsaturated single cell oil (SCO) using oleaginous fungi, Mucor circinelloides and Mortierella alpina. Both strains showed good growth and lipid accumulation when using animal fat as a single carbon source. The biomass concentration of 16.7 ± 2.2 gDCW/L and lipid content of 54.1%wt (of dry cell weight) were obtained for Mucor circinelloides in shake flask experiments, surpassing the biomass yield achieved in batch and fed-batch fermentation. In contrast, Mortierella alpina gave the highest biomass concentration (8.3 ± 0.3 gDCW/L) and lipid content (55.8%wt) in fed-batch fermentation. Fat grown Mortierella alpina was able to produce arachidonic acid (ARA), and the highest ARA content of 23.8%wt (of total lipid weight) was in fed-batch fermentation. Gamma-linolenic acid (GLA) was produced by both fungal strains. At the end of fed-batch fermentation, the GLA yields obtained for Mucor circinelloides and Mortierella alpina were 4.51%wt and 2.77%wt (of total lipid weight), respectively. This study demonstrates the production of unsaturated SCO-rich fungal biomass from animal fat by fermentation.

Cutaneotrichosporon oleaginosus: A Versatile Whole-Cell Biocatalyst for the Production of Single-Cell Oil from Agro-Industrial Wastes

Cutaneotrichosporon oleaginosus is an oleaginous yeast with several favourable qualities: It is fast growing, accumulates high amounts of lipids and has a very broad substrate spectrum. Its resistance to hydrolysis by-products makes it a promising biocatalyst for custom tailored microbial oils. C. oleaginosus can accumulate up to 60 wt.% of its biomass as lipids. This species is able to grow by using several compounds as a substrate, such as acetic acid, biodiesel-derived glycerol, N-acetylglucosamine, lignocellulosic hydrolysates, wastepaper and other agro-industrial wastes. This review is focused on state-of-the-art innovative and sustainable biorefinery schemes involving this promising yeast and second- and third-generation biomasses. Moreover, this review offers a comprehensive and updated summary of process strategies, biomass pretreatments and fermentation conditions for enhancing lipid production by C. oleaginosus as a whole-cell biocatalyst. Finally, an overview of the main industrial applications of single-cell oil is reported together with future perspectives.

Molecular characterization and genetic diversity of four undescribed novel oleaginous Mortierella alpina strains from Libya

Background: A large number of undiscovered fungal species still exist on earth, which can be useful for bioprospecting, particularly for single cell oil (SCO) production. Mortierella is one of the significant genera in this field and contains about hundred species. Moreover, M. alpina is the main single cell oil producer at commercial scale under this genus. Methods: Soil samples from four unique locations of North-East Libya were collected for the isolation of oleaginous Mortierella alpina strains by a serial dilution method. Morphological identification was carried out using light microscopy (Olympus, Japan) and genetic diversity of the isolated Mortierella alpina strains was assessed using conserved internal transcribed spacer (ITS) gene sequences available on the NCBI GenBank database for the confirmation of novelty. The nucleotide sequences reported in this study have been deposited at GenBank (accession no. MZ298831:MZ298835). The MultAlin program was used to align the sequences of closely related strains. The DNA sequences were analyzed for phylogenetic relationships by molecular evolutionary genetic analysis using MEGA X software consisting of Clustal_X v.2.1 for multiple sequence alignment. The neighbour-joining tree was constructed using the Kimura 2-parameter substitution model. Results: The present research study confirms four oleaginous fungal isolates from Libyan soil. These isolates (barcoded as MSU-101, MSU-201, MSU-401 and MSU-501) were discovered and reported for the first time from diverse soil samples of district Aljabal Al-Akhdar in North-East Libya and fall in the class: Zygomycetes; order: Mortierellales. Conclusions: Four oleaginous fungal isolates barcoded as MSU-101, MSU-201, MSU-401 and MSU-501 were identified and confirmed by morphological and molecular analysis. These fungal isolates showed highest similarity with Mortierella alpina species and can be potentialistic single cell oil producers. Thus, the present research study provides insight to the unseen fungal diversity and contributes to more comprehensive Mortierella alpina reference collections worldwide.

Morphological and Molecular Confirmation of Four Undescribed Oleaginous Species of Mortierella from Libya

A large number of undiscovered fungal species still exist on earth, which can be useful for the bioprospecting particularly the single cell oil (SCO) production. The present research study confirms four oleaginous fungal isolates from Libyan soil. These isolates (Barcoded as MSU-101, MSU-201, MSU-401 and MSU-501) were discovered and reported first time from diverse soil samples of district Aljabal Al-Akhdar in North-East Libya and fall in the class: Zygomycetes; order: Mortierellales. From the morphological and phylogenetic analysis, these isolates were identified and found as closest match with Mortierella alpina species. The present research study provides insight to the unseen fungal diversity and contributes to more comprehensive Mortierella alpina reference collections worldwide.