Rhyzopus Oryzae Research Articles

Antimicrobial photodynamic response in Rhyzopus oryzae

Mucormycosis is an extremely aggressive fungal disease that has a high mortality rate. Conventional treatment consists of high doses of antibiotics and antifungal agents associated with surgical resections, but even with this aggressive treatment, the mortality rate is still high. The antimicrobial photodynamic therapy (aPDT), also called photodynamic inactivation (PDI), it is an interesting alternative to antifungal therapy because it has non-specific biological site action and can also be an additional method of treatment in conjunction with surgery and antifungal therapy. In this work we studied the evaluation of the photodynamic antimicrobial response in different phases of fungus growth (conidium and hyphae in the white and black phases) and for different protocols of PDI with PDZ, varying the concentration of photosensitizer, the incubation time, the association with surfactant and the fluence of light at 660 nm. In this work, PDI showed great potential in the in vitro study of R. oryzae.

Bioprocessing of oilseed cakes by fungi consortia: Impact of enzymes produced on antioxidants release

Oilseed cakes (OC) present high potential as feedstock for the biobased industry. Biotechnological processes allow OC valorization by the production of diverse value-added products and simultaneously altering OC structure, improving their nutritional value, and boosting OC utilization in animal feed. This work explored the use of fungi consortium of two different species as a bioprocessing approach to improve the nutritional quality of OC, obtain enzymes and antioxidants by solid-state fermentation (SSF) of sunflower cake (SFC) and rapeseed cake (RSC). Rhyzopus oryzae and Aspergillus ibericus consortium led to the highest production of cellulase (135 U/g) and β-glucosidase (265 U/g) while maximum protease (228 U/g) was obtained with A. niger and R. oryzae consortium. Maximum xylanase production (886 U/g) was observed in SSF of RSC resulting in high hemicellulose reduction. The synergistic action of lignocellulosic enzymes resulted in extracts with increased antioxidant potential with possible application as food additives against oxidative stress.

Fungi Associated with Deterioration of Onion Variety (Colour)

The incidence of fungi associated with deterioration of three varieties of onion bulbs was investigated in Usmanu Danfodiyo University, Sokoto. The bulbs were purposively collected in sterile polyethene bags through random sampling from kasuwan daji in Sokoto and brought to Mycology Laboratory, Department of Biological Sciences for analysis. Samples were prepared using standard procedures for Isolation and Inoculation of fungal organisms. Isolates were identified based on Morphological and cultural identification using mycological atlas. Pathogenicity test was out carried out using standard procedures. The result obtained revealed the presence of Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus and Rhyzopus oryzae. R. oryzae had the highest percentage of occurrence (47.4%) in Red onion, A.niger and A. fumigatus had the highest occurrence (39.1%) in white onion, and in the purple onion A. niger and A. flavus had the highest percentage of occurrence with (42.8%). The pathogenicity test indicated that all the isolates were found to facilitate spoilage of the bulbs. R. oryzae was found to be more pronounced on white onion, A. niger was prominent in purple onion, A. flavus on red onion. Therefore, fungal spoilage of onion could be determined base on the type of fungal organisms and the type of onion variety. The study could help formers to detect the type of organisms that are responsible for spoilage on the different onion varieties thus, determine the appropriate type of pesticides to apply either in the field or on storage.

Degradation of lignocellulosic matrix of oilseed cakes by solid-state fermentation: fungi screening for enzymes production and antioxidants release.

Vegetable oils are yearly produced in large amounts generating solid by-products, the oilseed cake (OC). OCs are lignocellulosic materials that have been used for animal feed with some limitations due to high fibre content from the plant cell walls. Biotechnological processes can help to overcome these limitations and contribute to up-grading such by-products, enhancing their nutritional value as feed ingredients. All fungal species were able to decrease neutral detergent fibre and acid detergent fibre in all by-products. Additionally, relevant enzymes were produced by the three fungi studied resulting in an improved antioxidant capacity of all fermented OCs. Aspergillus niger led to the highest activity of cellulase (109 U g-1 ), xylanase (692 U g-1 ) and protease (157 U g-1 ) per dry OC matter and to the recovery of an extract rich in antioxidants, with the highest scavenging potential of free radicals and superoxide anion, iron chelation ability and reducing power. Rhyzopus oryzae produced the highest activity of β-glucosidase (503 U g-1 ) and led to the highest liberation of total phenolic content (TPC). Principal components analysis showed that extracts with high antioxidant potential were obtained in solid-state fermentation (SSF) with high enzymatic activity. A positive correlation was established between the action of β-glucosidase and TPC. Within the same bioprocess it was possible to improve the nutritional value of OCs and to obtain relevant bioactive compounds such as lignocellulosic enzymes and phenolic compounds with antioxidant potential, resulting in a significant improvement of already valuable by-products with commercial interest for animal feed. © 2021 Society of Chemical Industry.

Fungal Dysbiosis Correlates with the Development of Tumor-Induced Cachexia in Mice

Cachexia (CC) is a devastating metabolic syndrome associated with a series of underlying diseases that greatly affects life quality and expectancy among cancer patients. Studies involving mouse models, in which CC was induced through inoculation with tumor cells, originally suggested the existence of a direct correlation between the development of this syndrome and changes in the relative proportions of several bacterial groups present in the digestive tract. However, these analyses have focus solely on the characterization of bacterial dysbiosis, ignoring the possible existence of changes in the relative populations of fungi, during the development of CC. Thus, the present study sought to expand such analyses, by characterizing changes that occur in the gut fungal population (mycobiota) of mice, during the development of cancer-induced cachexia. Our results confirm that cachectic animals, submitted to Lewis lung carcinoma (LLC) transplantation, display significant differences in their gut mycobiota, when compared to healthy controls. Moreover, identification of dysbiotic fungi showed remarkable consistency across successive levels of taxonomic hierarchy. Many of these fungi have also been associated with dysbioses observed in a series of gut inflammatory diseases, such as obesity, colorectal cancer (CRC), myalgic encephalomyelitis (ME) and inflammatory bowel disease (IBD). Nonetheless, the dysbiosis verified in the LLC model of cancer cachexia seems to be unique, presenting features observed in both obesity (reduced proportion of Mucoromycota) and CRC/ME/IBD (increased proportions of Sordariomycetes, Saccharomycetaceae and Malassezia). One species of Mucoromycota (Rhyzopus oryzae) stands out as a promising probiotic candidate in adjuvant therapies, aimed at treating and/or preventing the development of CC.

Fumaric acid production by Rhyzopus oryzae in presence of n-dodecane as oxygen-vector

The production of fumaric acid by Rhyzopus oryzae has been investigated for two fermentation systems, namely batch and fed-batch fermentations. In both cases, n-dodecane has been added into the broth at various concentrations, this hydrocarbon acting as oxygen-vector, increasing the DO level and oxygen transfer rate. Higher oxygen concentration could lead to the inhibitory phenomenon, which is more pronounced at n-dodecane concentration over 10 % vol. For this reason, the highest fumaric acid concentration was reached for 5% vol. n-dodecane. The fed-batch system allowed to reaching higher concentrations of fumaric acid, regardless of n-dodecane volumetric fraction. Compared to the batch system, the productivity was for 1.2–1.4 times higher, the most important increase corresponding to 10 and 15 % vol. hydrocarbon, while the least important for 0 and 5% vol. hydrocarbon. The values of kLa for fed-batch regime were considerably lower compared to those recorded for batch fermentation, due to the cumulative effects of higher viscosity (highest rate of biomass accumulation) and smaller size of fungal pellets. On the basis of the experimental results, it was concluded that the optimum concentration level of n-dodecane for acid production in both fermentation systems is 5% vol.

Antioxidant activity and phytocemical analysis from black rice bran

Black rice bran is a one of potential antioxidant component source. Black rice bran bioactivity is better than white rice bran. However, the high bioactivity of black rice bran is not accompanied by its utilization as a functional food ingredient. The ability of R. oryzae to degrade lignocellulose and polysaccharide matrix through its enzyme activity is proven to increase antioxidant activity on rice bran variety of white rice. The capability of these molds on the black rice bran matrix is expected to maximize the potential functional properties of antioxidants. This study aims to determine the content of phytochemicals and antioxidants from black rice bran and the comparison between before and after being given fermentation treatment with addition of Rhyzopus oryzae. In this study, black rice bran was given two different treatment that is non-fermentation and fermentation using Rhizopus oryzae for 96 hours. After the cultivation period, each sample was extracted with methanol solvent. Further phytochemicals including flavonoid, alkaloid, tannin, saponin, quinone, steroid and triterpenois were evaluated by qualitative phytochemical tests while the antioxidant capacity was evaluated by DPPH assay. The results showed that the fermented black rice bran samples contained flavonoids, saponins and triterpenoid while non-fermented black rice bran sample contained flavonoids, tannins and steroids. Antioxidant activity of fermented black rice bran (67,37%) was more effective to inhibit free radicals than non fermented black rice bran (43,93%). According to the result, studies are needed to produce a black rice bran functional food product that can be used as a source of food containing bioactive compouns and antioxidants.

"Enhancement of fumaric acid production by rhyzopus oryzae using oxygen - vector "

"Enhancement of fumaric acid production by rhyzopus oryzae using oxygen - vector "

Uses of Rhizopus oryzae in the kitchen

The use of fungal cultures in modern cuisine can provide a broad number of new textures, flavors and tastes from unexpected substrates; such as fruits, vegetables and nuts. The presented research describes how Rhyzopus oryzae, a fungi used in Asian culture to produce traditional recipes, results in fruits, vegetables and grains with unique sensorial properties. Throughout the paper, different examples of these novelty uses are presented showing different examples of prototypes those have been successfully incorporated into our menus, their production procedures and their sensorial evaluations.

Postharvest soft rot on Citrullus vulgaris caused by Rhizopus oryzae in South Korea

During the summers of 2010 and 2011, a disease suspected to be Rhizopus soft rot was observed on watermelon at commercial markets in Jinju, South Korea. The infected parts of the mature fruits appeared water-soaked at first, and then softened and rotted rapidly. White mycelia grew from the primary infection site and gradually covered the fruit with tufted whisker-like gray sporangia and sporangiophores. To confirm the identity of the fungus, the complete internal transcribed spacer (ITS) rDNA sequence was amplified and sequenced. On the basis of the mycological characteristics, molecular identification and pathogenicity, the fungus was identified as Rhyzopus oryzae. This is the first note of R. oryzae as a postharvest pathogen of watermelon in Korea.

Cassava solid-state fermentation with a starter culture of Lactobacillus plantarum and Rhyzopus oryzae for cellulase production

A mixture of two microorganisms was used as starter culture, with the aims of producing cellulose from fermented cassava roots. Cellulase yields of 430 IU/g were recorded in solid-state fermentation of cassava starch with mixed culture of Lactobacillus plantarumand Rhyzopus oryzae, isolated from cassava dried chips. High cellulase activity (8.6 IU/ml) per unit volume of enzyme broth and high yields of cellulases were obtained and attributed to the growth of both strains on cellulose fraction of cassava roots. In Solid State Fermentation with Starter mix-culture (SSFS), fermentation retting was completed in two days, and significant softening was noticed. No significant softening was evidence in Solid State Sterile Fermentation (SSSF) and Liquid state fermentation (LSF). Keywords: Cassava, cellulases, Lactobacillus plantarum, Rhyzopus oryzae, solid state fermentation, liquid state fermentation.

Avaliação da atividade antifúngica de extratos fenólicos de cebola, farelo de arroz e microalga Chlorella phyrenoidosa

The objective of this work was to relate the levels of total phenolic in onion, rice bran, and Chlorellaphyrenoidosa with the antifungal activity tested against the fungus Rhyzopus oryzae. The phenolic compounds of onion were extracted in three solvent systems: aqueous, methanolic, and with ethila acetate, whereas the phenolic compounds of rice bran and Chlorella phyrenoidosa were extracted with methanol. The extracts were quantified with the Folin-Ciocalteau reagent. The method to evaluate the antifungal activity employed was the diluted Agar technique. The Rhyzopus oryzae had its development inhibited in the presence of onion methanolic and aceto-ethylic extracts and rice bran methanolic extracts at the following phenolic concentrations, 86; 2.6, and 46 µgphenolic.mL-1agar, respectively. The aqueous extracts from onion and the methanolic extract from Chlorellaphyrenoidosa did not inhibit fungal growth under the phenolic concentrations tested.

Carboxymethylcellulose and poly(vinyl alcohol) used as a film support for lipases immobilization

Lipases from 10 different sources were immobilized on poly(vinyl alcohol) (PVA), carboxymethycellulose (CMC) and poly(vinyl alcohol):carboxymethycellulose blend (50:50% m/m) and used as biocatalysts in esterification reactions of carboxylic acids with n-pentanol in organic media. Among the tested lipases, higher yields in n-pentyl laurate were obtained when lipases from Mucor javanicus (MJL) or Rhyzopus oryzae (ROL) were immobilized in CMC, PVA and CMC:PVA blend (70–99%). ROL was selected in the following experiments. The influence of ROL loading in the supports showed that 50 mg lipase/0.5 g support is sufficient to obtain the ester in quantitative yield (99%). The effect of temperature (25–50 °C) was also evaluated, and the highest yields (99%) were obtained after ROL was immobilized in the above supports. Lower yields were obtained using the enzyme in a free form (6–33%) regardless of the temperature. The influence of organic solvent was also considered for this reaction using ROL/free, ROL/PVA and ROL/CMC systems. Higher yields (99%) were obtained when non-polar solvents were used. ROL supported in PVA, CMC and CMC:PVA blend could be reused, at least, 10 times during an 80-day period, keeping its enzyme activity and macroscopic properties (yields in the range of 77–99%). Using ROL in a free form, ROL lost its activity completely after six reactional cycles. The influence of acyl donor was also studied using an ROL/PVA system and n-hexane as an organic solvent. A dependence on carbon number of the alkyl chain was observed. Higher yields (99%) were observed for fatty acids with more than 10 carbon atoms. These results showed that polymers such as PVA, CMC and CMC:PVA blends can be used successfully as alternative materials for lipase immobilization.

Reversible and strong immobilization of proteins by ionic exchange on supports coated with sulfate-dextran.

New and strong ionic exchange resins have been prepared by the simple and rapid ionic adsorption of anionic polymers (sulfate-dextran) on porous supports activated with the opposite ionic group (DEAE/MANAE). Ionic exchange properties of such composites were strongly dependent on the size of the ionic polymers as well as on the conditions of the ionic coating of the solids with the ionic polymers (optimal conditions were 400 mg of sulfate-dextran 5000 kDa per gram of support). Around 80% of the proteins contained in crude extracts from Escherichia coli and Acetobacter turbidans could be adsorbed on these porous composites even at pH 7. This interaction was stronger than that using conventional carboxymethyl cellulose (CMC) and even others such as supports coated with aspartic-dextran polymer. By means of the sequential use of the new supports and supports coated with polyethyleneimine (PEI), all proteins from crude extracts could be immobilized. In fact, a large percentage (over 50%) could be immobilized on both supports. Finally, some industrially relevant enzymes (beta-galactosidases from Aspergillus oryzae, Kluyveromyces lactis, and Thermussp. strain T2, lipases from Candida antarctica A and B, Candida rugosa, Rhizomucor miehei, and Rhyzopus oryzae and bovine pancreas trypsin and chymotrypsin) have been immobilized on these supports with very high activity recoveries and immobilization rates. After enzyme inactivation, the protein could be fully desorbed from the support, and then the support could be reused for several cycles. Moreover, in some instances the enzyme stability was significantly improved, mainly in the presence of organic solvents, perhaps as a consequence of the highly hydrophilic microenvironment of the support.

L(+)-Lactic acid production from corncobs by Rhizopus oryzae NRRL-395

Corncobs were used as a substrate for production of l(+)-lactic acid by Rhyzopus oryzae NRRL-395. The concentrations of CaCO 3, corncobs and Rapidase Pomaliq, a commercial apple juice processing enzyme preparation were found to significantly enhance lactic acid production by the mold. Under optimal conditions (0.2 g/100 mL CaCO 3, 0.5 mL/100 mL Rapidase Pomaliq, and 5 g/100 mL corncobs), R. oryzae NRRL-395 yielded 299.4±6.8 g per kg dry matter of corncobs after 48 h of fermentation at 30°C.

High-level ethanol production from starch by a flocculent Saccharomyces cerevisiae strain displaying cell-surface glucoamylase.

A Strain of host yeast YF207, which is a tryptophan auxotroph and shows strong flocculation ability, was obtained from SaccharomYces diastaticus ATCC60712 and S. cerevisiae W303-1B by tetrad analysis. The plasmid pGA11, which is a multicopy plasmid for cell-surface expression of the Rhyzopus oryzae glucoamylase/alpha-agglutinin fusion protein, was then introduced into this flocculent yeast strain (YF207/pGA11). Yeast YF207/pGA11 grew rapidly under aerobic condition (dissolved oxygen 2.0 ppm), using soluble starch. The harvested cells were used for batch fermentation of soluble starch to ethanol under anaerobic condition and showed high ethanol production rates (0.71 g h(-1) l(-1)) without a time lag, because glucoamylase was immobilized on the yeast cell surface. During repeated utilization of cells for fermentation, YF207/pGA11 maintained high ethanol production rates over 300 h. Moreover, in fed-batch fermentation with YF207/pGA11 for approximately 120 h, the ethanol concentration reached up to 50 g l(-1). In conclusion, flocculent yeast cells displaying cell-surface glucoamylase are considered to be very effective for the direct fermentation of soluble starch to ethanol.