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Applied Microbiology and Biotechnology May 2012Rhizopus oryzae is a filamentous fungus belonging to the Zygomycetes. It is among others known for its ability to produce the sustainable platform chemicals L:... (Review)
Review
Rhizopus oryzae is a filamentous fungus belonging to the Zygomycetes. It is among others known for its ability to produce the sustainable platform chemicals L: -(+)-lactic acid, fumaric acid, and ethanol. During glycolysis, all fermentable carbon sources are metabolized to pyruvate and subsequently distributed over the pathways leading to the formation of these products. These platform chemicals are produced in high yields on a wide range of carbon sources. The yields are in excess of 85 % of the theoretical yield for L: -(+)-lactic acid and ethanol and over 65 % for fumaric acid. The study and optimization of the metabolic pathways involved in the production of these compounds requires well-developed metabolic engineering tools and knowledge of the genetic makeup of this organism. This review focuses on the current metabolic engineering techniques available for R. oryzae and their application on the metabolic pathways of the main fermentation products.
Topics: Biotransformation; Carbon; Ethanol; Fumarates; Lactic Acid; Metabolic Engineering; Metabolic Networks and Pathways; Rhizopus
PubMed: 22526790
DOI: 10.1007/s00253-012-4033-0 -
Microbial Cell Factories Aug 2023Using fungal biomass for biocatalysis is a potential solution for the expensive cost of the use o enzymes. Production of fungal biomass with effective activity requires...
BACKGROUND
Using fungal biomass for biocatalysis is a potential solution for the expensive cost of the use o enzymes. Production of fungal biomass with effective activity requires optimizing the cultivation conditions.
RESULTS
Rhizopus stolonifer biomass was optimized for transesterification and hydrolysis of waste frying oil (WFO). Growth and biomass lipolytic activities of R. stolonifer improved under shaking conditions compared to static conditions, and 200 rpm was optimum. As biomass lipase and transesterification activities inducer, olive oil was superior to soybean, rapeseed, and waste frying oils. Biomass produced in culture media containing fishmeal as an N-source feedstock had higher lipolytic capabilities than corn-steep liquor and urea. Plackett Burman screening of 9 factors showed that pH (5-9), fishmeal (0.25-1.7%, w/v), and KHPO (0.1-0.9%, w/v) were significant factors with the highest main effect estimates 11.46, 10.42, 14.90, respectively. These factors were selected for response surface methodology (RSM) optimization using central composite design (CCD). CCD models for growth, biomass lipase activity, and transesterification capability were significant. The optimum conditions for growth and lipid modification catalytic activities were pH 7.4, fishmeal (2.62%, w/v), and KH2PO4 (2.99%, w/v).
CONCLUSION
Optimized culture conditions improved the whole cell transesterification capability of Rhizopus stolonifer biomass in terms of fatty acid methyl ester (FAME) concentration by 67.65% to a final FAME concentration of 85.5%, w/w.
Topics: Biomass; Esterification; Fatty Acids; Rhizopus; Lipase; Biofuels
PubMed: 37580714
DOI: 10.1186/s12934-023-02141-y -
MBio Sep 2020Fungal-bacterial symbioses range from antagonisms to mutualisms and remain one of the least understood interdomain interactions despite their ubiquity as well as...
Fungal-bacterial symbioses range from antagonisms to mutualisms and remain one of the least understood interdomain interactions despite their ubiquity as well as ecological and medical importance. To build a predictive conceptual framework for understanding interactions between fungi and bacteria in different types of symbioses, we surveyed fungal and bacterial transcriptional responses in the mutualism between () (ATCC 52813, host) and its (formerly ) endobacteria versus the antagonism between a nonhost (ATCC 11559) and isolated from the host, at two time points, before and after partner physical contact. We found that bacteria and fungi sensed each other before contact and altered gene expression patterns accordingly. did not discriminate between the host and nonhost and engaged a common set of genes encoding known as well as novel symbiosis factors. In contrast, responses of the host versus nonhost to endobacteria were dramatically different, converging on the altered expression of genes involved in cell wall biosynthesis and reactive oxygen species (ROS) metabolism. On the basis of the observed patterns, we formulated a set of hypotheses describing fungal-bacterial interactions and tested some of them. By conducting ROS measurements, we confirmed that nonhost fungi increased production of ROS in response to endobacteria, whereas host fungi quenched their ROS output, suggesting that ROS metabolism contributes to the nonhost resistance to bacterial infection and the host ability to form a mutualism. Overall, our study offers a testable framework of predictions describing interactions of early divergent Mucoromycotina fungi with bacteria. Animals and plants interact with microbes by engaging specific surveillance systems, regulatory networks, and response modules that allow for accommodation of mutualists and defense against antagonists. Antimicrobial defense responses are mediated in both animals and plants by innate immunity systems that owe their functional similarities to convergent evolution. Like animals and plants, fungi interact with bacteria. However, the principles governing these relations are only now being discovered. In a study system of host and nonhost fungi interacting with a bacterium isolated from the host, we found that bacteria used a common gene repertoire to engage both partners. In contrast, fungal responses to bacteria differed dramatically between the host and nonhost. These findings suggest that as in animals and plants, the genetic makeup of the fungus determines whether bacterial partners are perceived as mutualists or antagonists and what specific regulatory networks and response modules are initiated during each encounter.
Topics: Antibiosis; Bacteria; Burkholderia; Fungi; Gene Expression Profiling; Rhizopus; Signal Transduction; Symbiosis
PubMed: 32900811
DOI: 10.1128/mBio.02088-20 -
Antimicrobial Agents and Chemotherapy Aug 2019Recently, the species concept of opportunistic and its relatives has been revised, resulting in the recognition of its classical formae as independent species and the...
Recently, the species concept of opportunistic and its relatives has been revised, resulting in the recognition of its classical formae as independent species and the description of new species. In this study, we used isolates of all clinically relevant species and performed susceptibility testing using the EUCAST reference method to identify potential species-specific susceptibility patterns. susceptibility profiles of 101 mucoralean strains belonging to the genus (72), the closely related species (3), (12), (10), and (4) to six antifungals (amphotericin B, natamycin, terbinafine, isavuconazole, itraconazole, and posaconazole) were determined. The most active drug for all Mucorales was amphotericin B. Antifungal susceptibility profiles of pathogenic species were specific for isavuconazole, itraconazole, and posaconazole. The species formerly united in showed clear differences in their antifungal susceptibilities. , , ( f. ), and exhibited high MICs to all azoles tested. presented high MICs for isavuconazole and posaconazole, and and showed high MICs for isavuconazole. MIC values of spp. for posaconazole, isavuconazole, and itraconazole were high compared to those for and the Lichtheimiaceae ( and ). Molecular identification combined with susceptibility testing is recommended for species, especially if azoles are applied in treatment.
Topics: Amphotericin B; Antifungal Agents; Humans; Itraconazole; Microbial Sensitivity Tests; Mucor; Mucormycosis; Natamycin; Nitriles; Pyridines; Rhizopus; Species Specificity; Terbinafine; Triazoles
PubMed: 31182532
DOI: 10.1128/AAC.00653-19 -
Molecules (Basel, Switzerland) Mar 2023The identification and potential bioaccessibility of phenolic compounds using the highly sensitive micro-HPLC-QTRAP/MS/MS technique and Maillard reaction products (MRPs)...
The identification and potential bioaccessibility of phenolic compounds using the highly sensitive micro-HPLC-QTRAP/MS/MS technique and Maillard reaction products (MRPs) in buckwheat biscuits formulated from flours, raw and roasted, fermented by 2710 was addressed in this study after in vitro digestion. The content of the analyzed MRPs such as furosine, FAST index, and the level of melanoidins defined by the browning index was increased in the biscuits prepared from fermented flours as compared to the control biscuits prepared from non-fermented ones. After in vitro digestion higher content of furosine was observed in control and tested biscuits providing its high potential bioaccessibility. The fermented buckwheat flours used for baking affected the nutritional value of biscuits in comparison to the control biscuits in the context of the twice-increased FAST index. More than three times higher value of the browning index was noted in control and tested biscuits after digestion in vitro indicating the high bioaccessibility of melanoidins. Our results showed the presence of ten phenolic acids and eight flavonoids in the investigated biscuits. Among phenolic acids, vanillic, syringic, and protocatechuic were predominant while in the group of flavonoids, rutin, epicatechin, and vitexin were the main compounds in analyzed biscuits. Generally, the lower potential bioaccessibility of phenolic acids and higher potential bioaccessibility of flavonoids was found for biscuits obtained from buckwheat flours fermented by fungi compared to control biscuits obtained from non-fermented flours. Fermentation of buckwheat flour with the fungus 2710 seems to be a good way to obtain high-quality biscuits; however, further research on their functional properties is needed.
Topics: Flour; Fagopyrum; Tandem Mass Spectrometry; Phenols; Flavonoids; Glycation End Products, Advanced; Rhizopus
PubMed: 36985718
DOI: 10.3390/molecules28062746 -
Journal of Clinical Microbiology Jun 2018
Topics: Adolescent; Adult; Aged; Communicable Diseases, Emerging; DNA, Intergenic; Diabetes Complications; Diabetes Mellitus; Female; Humans; Immunocompromised Host; India; Infant; Male; Middle Aged; Mucormycosis; Phylogeny; Rhizopus; Young Adult
PubMed: 29563203
DOI: 10.1128/JCM.00433-18 -
BMJ Case Reports Feb 2013Mucormycosis is a rare fungal infection that affects immunocompromised patients, and the rhinoorbitocerebral presentation is the most common clinical form of the... (Review)
Review
Mucormycosis is a rare fungal infection that affects immunocompromised patients, and the rhinoorbitocerebral presentation is the most common clinical form of the disease, often associated with diabetes mellitusThe treatment is complex and involves amphotericin B and surgery. Studies show increasing success without or with minimal surgeries. The authors present the case of a diabetic woman with a 1-month history of intranasal and right periorbital pain associated with progressive deficit of various cranial nerves, sudden amaurosis and homolateral ptosis. Rhizopus oryzae species was identified in pus in the nasal mucosa. She was treated with antifungal therapy and minimal surgical debridement with success. The authors decided on publication because of the rarity of this entity, alerting for the need of a high suspicion index for the diagnosis, which should be made as early as possible due to the high mortality rate, as well as presenting data about the increasing discussion of therapeutic strategies, with some new approaches that prioritise minimal surgeries.
Topics: Amphotericin B; Central Nervous System Fungal Infections; Debridement; Diabetes Mellitus, Type 2; Female; Humans; Immunocompromised Host; Middle Aged; Mucormycosis; Nose Diseases; Orbital Diseases; Rhizopus; Treatment Outcome; Turbinates
PubMed: 23389725
DOI: 10.1136/bcr-2013-008552 -
Journal of Industrial Microbiology &... Jun 2008The fungus Rhizopus oryzae converts both glucose and xylose under aerobic conditions into chirally pure L+-lactic acid with by-products such as xylitol, glycerol,...
The fungus Rhizopus oryzae converts both glucose and xylose under aerobic conditions into chirally pure L+-lactic acid with by-products such as xylitol, glycerol, ethanol, carbon dioxide and fungal biomass. In this paper, we demonstrate that the production of lactic acid by R. oryzae CBS 112.07 only occurs under growing conditions. Deprivation of nutrients such as nitrogen, essential for fungal biomass formation, resulted in a cessation of lactic acid production. Complete xylose utilisation required a significantly lower C/N ratio (61/1) compared to glucose (201/1), caused by higher fungal biomass yields that were obtained with xylose as substrate. Decreasing the oxygen transfer rate resulted in decline of xylose consumption rates, whereas the conversion of glucose by R. oryzae was less affected. Both results were linked to the fact that R. oryzae CBS 112.07 utilises xylose via the two-step reduction/oxidation route. The consequences of these effects for R. oryzae as a potential lactic acid producer are discussed.
Topics: Enzymes; Fermentation; Glucose; Lactic Acid; Oxygen; Rhizopus; Xylose
PubMed: 18247072
DOI: 10.1007/s10295-008-0318-9 -
PloS One 2020Pathogenic mucormycetes induce diseases with considerable morbidity and mortality in immunocompromised patients. Virulence data comparing different Mucorales species and... (Comparative Study)
Comparative Study
Pathogenic mucormycetes induce diseases with considerable morbidity and mortality in immunocompromised patients. Virulence data comparing different Mucorales species and various underlying risk factors are limited. We therefore compared the pathogenesis of inhalative infection by Rhizopus (R.) arrhizus and Lichtheimia (L.) corymbifera in murine models for predominant risk factors for onset of infection. Mice with diabetes or treated with cyclophosphamide or cortisone acetate were challenged via the intranasal route with an isolate of R. arrhizus or L. corymbifera, respectively. Clinical, immunological and inflammation parameters as well as efficacy of posaconazole prophylaxis were monitored over 14 days. Whereas immunocompetent mice showed no clinical symptoms after mucormycete infection, mice treated with either cyclophosphamide (CP) or cortisone acetate (CA) were highly susceptible. Animals infected with the isolate of R. arrhizus showed prolonged survival and lower mortality, compared to those exposed to the L. corymbifera isolate. This lower virulence of R. arrhizus was risk factor-dependent, since diabetic mice died only after infection with Rhizopus, whereas all Lichtheimia-infected diabetic animals survived. Under posaconazole prophylaxis, both mucormycetes were able to establish breakthrough infections in CA- and CP-treated mice, but the course of infection was significantly delayed. Detailed analysis revealed that susceptibility of CA- and CP-treated mice could not be mimicked by exclusive lack or downmodulation of neutrophils, platelets or complement, but can be supposed to be the consequence of a broad immunosuppressive effect induced by the drugs. Both Lichtheimia corymbifera and Rhizopus arrhizus induce invasive mycoses in immunocompromised hosts after inhalative infection. Key parameters such as virulence and immunopathogenesis vary strongly according to fungal species and underlying risk group. Selected neutropenia is no sufficient risk factor for onset of inhalative mucormycosis.
Topics: Animals; Disease Models, Animal; Female; Inhalation; Mice; Mice, Inbred C57BL; Mucorales; Mucormycosis; Rhizopus; Survival Analysis; Triazoles
PubMed: 32555589
DOI: 10.1371/journal.pone.0234063 -
Nature Microbiology Mar 2021Fungi of the order Mucorales cause mucormycosis, a lethal infection with an incompletely understood pathogenesis. We demonstrate that Mucorales fungi produce a toxin,...
Fungi of the order Mucorales cause mucormycosis, a lethal infection with an incompletely understood pathogenesis. We demonstrate that Mucorales fungi produce a toxin, which plays a central role in virulence. Polyclonal antibodies against this toxin inhibit its ability to damage human cells in vitro and prevent hypovolemic shock, organ necrosis and death in mice with mucormycosis. Inhibition of the toxin in Rhizopus delemar through RNA interference compromises the ability of the fungus to damage host cells and attenuates virulence in mice. This 17 kDa toxin has structural and functional features of the plant toxin ricin, including the ability to inhibit protein synthesis through its N-glycosylase activity, the existence of a motif that mediates vascular leak and a lectin sequence. Antibodies against the toxin inhibit R. delemar- or toxin-mediated vascular permeability in vitro and cross react with ricin. A monoclonal anti-ricin B chain antibody binds to the toxin and also inhibits its ability to cause vascular permeability. Therefore, we propose the name 'mucoricin' for this toxin. Not only is mucoricin important in the pathogenesis of mucormycosis but our data suggest that a ricin-like toxin is produced by organisms beyond the plant and bacterial kingdoms. Importantly, mucoricin should be a promising therapeutic target.
Topics: Animals; Antitoxins; Apoptosis; Capillary Permeability; Cells, Cultured; Cross Reactions; Humans; Hyphae; Lectins; Mice; Mucorales; Mucormycosis; Mycotoxins; Necrosis; RNA Interference; Rhizopus; Ribosome Inactivating Proteins; Ricin; Virulence
PubMed: 33462434
DOI: 10.1038/s41564-020-00837-0