Rhizomucor pusillus
Rhizomucor pusillus is a thermophilic filamentous fungus belonging to the family Lichtheimiaceae, within the order Mucorales.[1][2] It is known for its role in various industrial applications, particularly in enzyme production and food fermentation, and has been studied for its safety and potential use in human consumption.
| Rhizomucor pusillus | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Mucoromycota |
| Class: | Mucoromycetes |
| Order: | Mucorales |
| Family: | Lichtheimiaceae |
| Genus: | Rhizomucor |
| Species: | R. pusillus
|
| Binomial name | |
| Rhizomucor pusillus (Lindt) Schipper
| |
Diversity and ecology
[edit]Rhizomucor pusillus belongs to the order Mucorales and the class Mucoromycetes. R. pusillus is a member of the phylum Mucoromycota (previously Zygomycota), which includes Rhizopus microsporus, R. oligosporus, and R. oryzae, fungi that have been used for centuries to produce tempeh from the fermentation of soybeans.[3] The Mucorales order belongs to the early diverging ancient fungi and is characterized by rapidly growing mycelium and amorph structures formed in large quantities.[1] The Rhizomucor genus can be recognized by a morphology intermediate between Rhizopus and Mucor.[4] R. pusillus is a filamentous fungus that is known as a pioneer species in compost, quickly utilizing easily accessible substrates.[5][6]
Currently, around 10 different Rhizomucor species are known, among which R. pusillus, R. miehei, and R. variabilis.[7] R. pusillus can grow at temperatures between 40-70 °C and is known for its thermostable enzyme production.[8][9] R. pusillus is predominantly found in geothermal places that create and produce heat, such as compost piles, garbage, or landfills.
Applications in food industry
[edit]Fermentation has a long history of use in the preservation and production of foods like soy sauce, yogurt, and alcoholic beverages. With the current advances in technology, the cultivation of fungi, in the form of fungal biomass, can be used to produce protein- and fiber-rich ingredients for human consumption. A well-known example of fungal biomass is Quorn (produced via fermentation of Fusarium venenatum), which has been on the international market for decades as a meat replacer.[10] Rhizomucor species have also emerged as a promising source for food applications. Both R. pusillus and R. miehei are reported to be used to produce milk-clotting enzymes for cheese manufacturing. Primarily R. miehei has been used for enzyme preparations by industrial biotechnology companies, such as Novozymes, in food.[11] Furthermore, Rhizomucor species have been isolated from different starter cultures of typical Asian fermented food products.[12][13]
Safety
[edit]Toxicological evaluation
[edit]Studies have demonstrated that R. pusillus can be safely used to produce a novel mycoprotein through fermentation.[14][15] R. pusillus used for the production of this mycoprotein cannot produce mycotoxins which are toxins produced by certain moulds (fungi) that can cause adverse health effects. The whole genome sequence of this strain was annotated and no genetic elements were found that share significant sequence homology with protein toxins, including the absence of mucoricin, an essential toxin in the pathogenesis of mucormycosis.[14] Furthermore, this mycoprotein produced via fermentation of R. pusillus did not exert genotoxic effects such as gene mutations or chromosomal aberrations.[16]
For foods containing novel proteins, potential allergenicity of the proteins is a key safety consideration. One such product is a fungal biomass obtained from the fermentation of Rhizomucor pusillus. Scaife et al (2024) concluded that based on in silico analyses and a literature review, the risk of allergenic cross-reactivity of R. pusillus is low.[17]
Regulatory approval
[edit]A R. pusillus strain has obtained regulatory approvals for food use, including self-affirmed GRAS (Generally Recognized as Safe) status in the United States and novel food approval in Singapore.[18]
Roles in disease
[edit]Mucorales fungi, especially Mucor species, can lead to serious but rare fungal infections in humans, called mucormycosis. Mucormycosis is most commonly caused by Rhizopus or Mucor species, affects the sinuses or the lungs and causes symptoms like cough, nasal congestion, and fever.[19][20] Although mucormycosis can be fatal, it occurs primarily in patients who are severely immunocompromised or with severe metabolic diseases. Mucorales do most frequently enter the body via the respiratory tract, through inhalation of spores.[19][20] Spores may also enter the body through the gastrointestinal tract or directly through the skin in case of trauma, wounds, catheters, and contaminated surgical devices. Infections with Mucorales have remained extremely rare compared to their abundance in our daily life. Fungal spores are ubiquitous in the air and are inhaled regularly. It is highly improbable that healthy individuals are infected upon ingestion of fungi since the invasion occurs mainly through inhalation of spores, which can then germinate and grow in the host. There is no evidence of mucormycosis caused by ingestion of mycelium from fungi or foods containing fungi, as they are most often heat-inactivated, which kills vegetative cells and spores. Additionally, Rhizomucor species have been shown to cause less than 5% of mucormycoses cases.[20] Mucoricin, an essential toxin in the pathogenesis of mucormycosis, is absent in R. pusillus.[14]
References
[edit]- ^ a b Hoffmann, K.; Pawłowska, J.; Walther, G.; Wrzosek, M.; de Hoog, G.S.; Benny, G.L.; Kirk, P.M.; Voigt, K. (2013-06-30). "The family structure of the Mucorales: a synoptic revision based on comprehensive multigene-genealogies". Persoonia - Molecular Phylogeny and Evolution of Fungi. 30 (1): 57–76. doi:10.3767/003158513X666259. PMC 3734967. PMID 24027347.
- ^ Steindorff, Andrei S.; Aguilar-Pontes, Maria Victoria; Robinson, Aaron J.; Andreopoulos, Bill; LaButti, Kurt; Kuo, Alan; Mondo, Stephen; Riley, Robert; Otillar, Robert; Haridas, Sajeet; Lipzen, Anna; Grimwood, Jane; Schmutz, Jeremy; Clum, Alicia; Reid, Ian D. (2024-09-12). "Comparative genomic analysis of thermophilic fungi reveals convergent evolutionary adaptations and gene losses". Communications Biology. 7 (1): 1124. doi:10.1038/s42003-024-06681-w. ISSN 2399-3642. PMC 11393059. PMID 39266695.
- ^ Teoh, Sze Qi; Chin, Nyuk Ling; Chong, Chun Wie; Ripen, Adiratna Mat; How, Syahmeer; Lim, Joyce Jen Li (2024-06-01). "A review on health benefits and processing of tempeh with outlines on its functional microbes". Future Foods. 9: 100330. doi:10.1016/j.fufo.2024.100330. ISSN 2666-8335.
- ^ Wanger, Audrey; Chavez, Violeta; Huang, Richard S.P.; Wahed, Amer; Actor, Jeffrey K.; Dasgupta, Amitava (2017), "Specific Clinical Infections", Microbiology and Molecular Diagnosis in Pathology, Elsevier, pp. 21–50, doi:10.1016/b978-0-12-805351-5.00003-x, ISBN 978-0-12-805351-5, retrieved 2025-01-28
- ^ Morgenstern, Ingo; Powlowski, Justin; Ishmael, Nadeeza; Darmond, Corinne; Marqueteau, Sandrine; Moisan, Marie-Claude; Quenneville, Geneviève; Tsang, Adrian (2012-04-01). "A molecular phylogeny of thermophilic fungi". Fungal Biology. 116 (4): 489–502. Bibcode:2012FunB..116..489M. doi:10.1016/j.funbio.2012.01.010. ISSN 1878-6146.
- ^ Satyanarayana, Tulasi; Littlechild, Jennifer; Kawarabayasi, Yutaka, eds. (2013). "Thermophilic Microbes in Environmental and Industrial Biotechnology". SpringerLink. doi:10.1007/978-94-007-5899-5. ISBN 978-94-007-5898-8.
- ^ "Index Fungorum - Search Page". www.indexfungorum.org. Retrieved 2025-01-28.
- ^ He, Zhenggui; Zhang, Lujia; Mao, Youzhi; Gu, Jingchao; Pan, Qi; Zhou, Sixing; Gao, Bei; Wei, Dongzhi (2014-12-24). "Cloning of a novel thermostable glucoamylase from thermophilic fungus Rhizomucor pusillus and high-level co-expression with α-amylase in Pichia pastoris". BMC Biotechnology. 14 (1): 114. doi:10.1186/s12896-014-0114-8. ISSN 1472-6750. PMC 4362842. PMID 25539598.
- ^ Hüttner, Silvia; Granchi, Zoraide; Nguyen, Thanh Thuy; van Pelt, Sake; Larsbrink, Johan; Thanh, Vu Nguyen; Olsson, Lisbeth (2018-12-01). "Genome sequence of Rhizomucor pusillus FCH 5.7, a thermophilic zygomycete involved in plant biomass degradation harbouring putative GH9 endoglucanases". Biotechnology Reports. 20: e00279. doi:10.1016/j.btre.2018.e00279. ISSN 2215-017X. PMC 6132078. PMID 30211016.
- ^ "Food Ingredients & Chemicals". Marlow Foods Limited. Retrieved 2025-01-28.
- ^ Rodrigues, Rafael C.; Fernandez-Lafuente, Roberto (2010-06-01). "Lipase from Rhizomucor miehei as an industrial biocatalyst in chemical process". Journal of Molecular Catalysis B: Enzymatic. 64 (1): 1–22. doi:10.1016/j.molcatb.2010.02.003. ISSN 1381-1177.
- ^ Hong, Seung-Beom; Kim, Dae-Ho; Lee, Mina; Baek, Seong-Yeol; Kwon, Soon-wo; Houbraken, Jos; Samson, Robert A. (2012-06-01). "Zygomycota associated with traditional meju, a fermented soybean starting material for soy sauce and soybean paste". Journal of Microbiology. 50 (3): 386–393. doi:10.1007/s12275-012-1437-6. ISSN 1976-3794. PMID 22752901.
- ^ Nurdini, A.; Nuraida, L.; Suwanto, A.; Suliantari (2015). "Microbial growth dynamics during tempe fermentation in two different home industries". International Food Research Journal. S2CID 27006181.
- ^ a b c Scaife, Kevin; Vo, Trung D.; Dommels, Yvonne; Leune, Elisa; Albermann, Kaj; Pařenicová, Lucie (2023-09-01). "In silico and in vitro safety assessment of a fungal biomass from Rhizomucor pusillus for use as a novel food ingredient". Food and Chemical Toxicology. 179: 113972. doi:10.1016/j.fct.2023.113972. ISSN 0278-6915.
- ^ Spiegel, Marjolein van der; Driessche, José J. van den; Leune, Elisa; Pařenicová, Lucie; Laat, Wim de (2020-12-01). "Safety Evaluation of Fermotein: Allergenicity, Mycotoxin Production, Biochemical Analyses and Microbiology of a Fungal Single-cell Protein Product". European Journal of Nutrition & Food Safety: 146–155. doi:10.9734/ejnfs/2020/v12i1030311. ISSN 2347-5641.
- ^ Spiegel, Marjolein Van Der; Driessche, José J. Van Den; Leune, Elisa; Knobel, Kirsten; Laat, Wim De (2021-07-05). "Fermotein Does Not Exert Genotoxic Effects in Bacterial Reverse Mutation and in Vitro Mammalian Cell Micronucleus Tests". European Journal of Nutrition & Food Safety: 113–123. doi:10.9734/ejnfs/2021/v13i330396. ISSN 2347-5641.
- ^ Scaife, Kevin; Taylor, Steve L.; Pařenicová, Lucie; Goodman, Richard E.; Vo, Trung D.; Leune, Elisa; Abdelmoteleb, Mohamed; Dommels, Yvonne (June 2024). "In silico evaluation of the potential allergenicity of a fungal biomass from Rhizomucor pusillus for use as a novel food ingredient". Regulatory Toxicology and Pharmacology. 150: 105629. doi:10.1016/j.yrtph.2024.105629. ISSN 0273-2300. PMID 38657894.
- ^ Mridul, Anay (2024-03-27). "The Protein Brewery Earns US & Singapore Regulatory Approval for Fermotein". Green Queen. Retrieved 2025-01-28.
- ^ a b Cornely, Oliver A; Alastruey-Izquierdo, Ana; Arenz, Dorothee; Chen, Sharon C A; Dannaoui, Eric; Hochhegger, Bruno; Hoenigl, Martin; Jensen, Henrik E; Lagrou, Katrien; Lewis, Russell E; Mellinghoff, Sibylle C; Mer, Mervyn; Pana, Zoi D; Seidel, Danila; Sheppard, Donald C (December 2019). "Global guideline for the diagnosis and management of mucormycosis: an initiative of the European Confederation of Medical Mycology in cooperation with the Mycoses Study Group Education and Research Consortium". The Lancet. Infectious Diseases. 19 (12): e405 – e421. doi:10.1016/S1473-3099(19)30312-3. ISSN 1473-3099. PMC 8559573. PMID 31699664.
- ^ a b c Roden, Maureen M.; Zaoutis, Theoklis E.; Buchanan, Wendy L.; Knudsen, Tena A.; Sarkisova, Tatyana A.; Schaufele, Robert L.; Sein, Michael; Sein, Tin; Chiou, Christine C.; Chu, Jaclyn H.; Kontoyiannis, Dimitrios P.; Walsh, Thomas J. (2005-09-01). "Epidemiology and Outcome of Zygomycosis: A Review of 929 Reported Cases". Clinical Infectious Diseases. 41 (5): 634–653. doi:10.1086/432579. ISSN 1058-4838. PMID 16080086.
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