Wood-feeding termite gut symbionts as an obscure yet promising source of novel manganese peroxidase-producing oleaginous yeasts intended for azo dye decolorization and biodiesel production

Abstract

Background The ability of oxidative enzyme-producing micro-organisms to efficiently valorize organic pollutants is critical in this context. Yeasts are promising enzyme producers with potential applications in waste management, while lipid accumulation offers significant bioenergy production opportunities. The aim of this study was to explore manganese peroxidase-producing oleaginous yeasts inhabiting the guts of wood-feeding termites for azo dye decolorization, tolerating lignocellulose degradation inhibitors, and biodiesel production. Results Out of 38 yeast isolates screened from wood-feeding termite gut symbionts, nine isolates exhibited high levels of extracellular manganese peroxidase (MnP) activity ranged between 23 and 27 U/mL after 5 days of incubation in an optimal substrate. Of these MnP-producing yeasts, four strains had lipid accumulation greater than 20% (oleaginous nature), with Meyerozyma caribbica SSA1654 having the highest lipid content (47.25%, w/w). In terms of tolerance to lignocellulose degradation inhibitors, the four MnP-producing oleaginous yeast strains could grow in the presence of furfural, 5-hydroxymethyl furfural, acetic acid, vanillin, and formic acid in the tested range. M. caribbica SSA1654 showed the highest tolerance to furfural (1.0 g/L), 5-hydroxymethyl furfural (2.5 g/L) and vanillin (2.0 g/L). Furthermore, M. caribbica SSA1654 could grow in the presence of 2.5 g/L acetic acid but grew moderately. Furfural and formic acid had a significant inhibitory effect on lipid accumulation by M. caribbica SSA1654, compared to the other lignocellulose degradation inhibitors tested. On the other hand, a new MnP-producing oleaginous yeast consortium designated as NYC-1 was constructed. This consortium demonstrated effective decolorization of all individual azo dyes tested within 24 h, up to a dye concentration of 250 mg/L. The NYC-1 consortium's decolorization performance against Acid Orange 7 (AO7) was investigated under the influence of several parameters, such as temperature, pH, salt concentration, and co-substrates (e.g., carbon, nitrogen, or agricultural wastes). The main physicochemical properties of biodiesel produced by AO7-degraded NYC-1 consortium were estimated and the results were compared to those obtained from international standards. Conclusion The findings of this study open up a new avenue for using peroxidase-producing oleaginous yeasts inhabiting wood-feeding termite gut symbionts, which hold great promise for the remediation of recalcitrant azo dye wastewater and lignocellulosic biomass for biofuel production. Graphical Abstract

Could termites be hiding a goldmine of obscure yet promising yeasts for energy crisis solutions based on aromatic wastes? A critical state-of-the-art review

“…While the association of some termites with fungi is well established, there are only a few reports of yeast–termite associations. Nowadays, eukaryotic expression systems, particularly yeasts inhabiting wood-feeding termite guts, are gaining increased attention for the enzymes they produce that have significant industrial applications, including biofuels and bioremediation [ 10 , 28 ].…”

“…The use of microbiomes in environmental systems could help to reduce waste, create a zero-pollution/toxic-free environment, address the plastic challenge, and create a sustainable blue economy [ 7 , 8 ]. Microbiomes, for example, can be used in environmental remediation by combining traditional techniques with microbial regeneration and incorporating microbiomes into a circular bioeconomy that valorizes waste [ 9 , 10 ]. Microbiomes are also critical in the development of microbial biobased polymers that are environmentally friendly.…”

“…The degradation of azo dyes by yeast-inhabiting wood-feeding termite gut symbionts resulted in the formation of aromatic amines (AAs), which are then mineralized to CO 2 and H 2 O [ 26 – 28 ]. Instead of amines, the termite gut yeasts degraded the azo dye Acid Orange 7, producing acetyl-CoA and TAG, which can be transesterified to produce biodiesel [ 9 , 10 ].…”

Exploring the therapeutic potential of acetonic plant extracts in the healing of skin wounds infected with multidrug resistant pathogens

“…For bacteria and fungi, phenotypic identification and conventional biochemical tests were carried out Sun, 2015, 2019;Ali et al, 2019b, c). Furthermore, isolated yeasts were identified using the protocols (Al-Tohamy et al, 2021). The isolates were biochemically identified using VITEK®2 automated systems (BioMérieux, Marcy-L'Étoile, France).…”

Environmental and Human Health Impact of Disposable Face Masks During the COVID-19 Pandemic: Wood-Feeding Termites as a Model for Plastic Biodegradation

“…Coloring FMs, like coloring any other type of fabric, serves primarily the purpose of boosting the items' visual attractiveness. In spite of the fact that they are used consistently in printing, textiles, and other applications, different dyes provide varying degrees of danger to the environment [15][16][17][18][19][20][21][22]. The vast majority of FMs that are sold commercially in order to limit the COVID-19 pandemic are made out of plastic layers, which are known to have negative impacts on both human health and the environment.…”