The potential of bioethanol production using different microbial inoculants for the simultaneous saccharification and fermentation of cassava peels from three cassava cultivars was investigated. ...Peels obtained from three cassava cultivars namely TME 0505, TME 419 and TME 4779, were washed, dried in a laboratory air oven dryer at 120 degree C for 3 h, ground into a fine texture and sieved with 1.5 mu nylon sieve. The sieved material was cultured using the following inoculant combinations: A = Rhizopus nigricans + Saccharomyces cerevisiae; B = Aspergillus niger + Saccharomyces cerevisiae; C = Rhizopus nigricans + Aspergillus niger + Saccharomyces cerevisiae; D = Rhizopus nigricans + Spirogyra africana + Saccharomyces cerevisae; E = Aspergillus niger + Spirogyra africana + Saccharomyces cerevisiae. These combinations have not been tested before on cassava peels. The control was inoculated with S. cerevisiae only. The cultures were distilled on the 21st day and the quantity of ethanol produced in each treatment group recorded. Results obtained showed significant differences (P<0.05) in the amount of ethanol produced and in its concentration among the five inoculants. Significant differences (P<0.05) were also obtained in ethanol yield from the three cassava varieties. Cassava peels from TME 4779 gave the highest ethanol yield of 14.46 plus or minus 2.08 g/cm3 using R. nigricans + S. africana+ S. cerevisiae. Similarly, cassava peels from TME 0505 gave the second highest ethanol yield of 13.33 plus or minus 0.67 g/cm3 using the same combination, namely R. nigricans + S. africana + S. cerevisiae. Low ethanol yields of 4.82 plus or minus 1.00, 6.43 plus or minus 0.58 and 7.77 plus or minus 0.88 g/cm3 were obtained from the cassava peels of TME 419, TME 0505 and TME 4779, respectively using S. cerevisiae alone. The yield reported in this study competes favorably with those reported from cassava peels, potato peels and millet husks using other inoculant treatments by other workers. Inoculants used in this study thus showed great potential for bioethanol production from cassava peels.
The 11α-hydroxylation of 16α, 17-epoxyprogesterone (EP) catalyzed by Rhizopus nigricans is crucial for the steroid industry. However, lower conversion rate of the biohydroxylation restricts its ...potential industrial application. The 11α-steroid hydroxylase CYP509C12 from R. oryzae were reported to play a crucial role in the 11α-hydroxylation in recombinant fission yeast. In the present study, the CYP509C12 of R. oryzae (RoCYP) was introduced into R. nigricans using the liposome-mediated mycelial transformation. Heterologous expression of RoCYP resulted in increased fungal growth and improved intracellular reactive oxygen species content in R. nigricans. The H
2
O
2
levels in RoCYP transformants were approximately 2-folder that of the R. nigricans wild type (RnWT) strain, with the superoxide dismutase activities increased approximately 45% and catalase activities decreased approximately 68%. Furthermore, the 11α-hydroxylation rates of EP in RoCYP transformants (C4, C6 and C9) were 39.7%, 38.3% and 38.7%, which were 12.1%, 8.2% and 9.4% higher than the rate of the RnWT strain, respectively. This paper investigated the effect of heterologous expression of RoCYP in R. nigricans, providing an effective genetic method to construct the engineered strains for steroid industry.
The nonviable biomass of
Aspergillus niger,
Aspergillus japonica,
Rhizopus nigricans,
Rhizopus arrhizus, and
Saccharomyces cerevisiae were screened for biosorption of textile dyes. The selected ...anionic reactive dyes were C.I. Reactive Black 8, C.I. Reactive Brown 9, C.I. Reactive Green 19, C.I. Reactive Blue 38, and C.I. Reactive Blue 3. Experiments were conducted at initial dye concentration of 50, 100, 150 and 200
mg/L. The effect of initial dye concentration, dose of biosorbent loading, temperature, and pH on adsorption kinetics was studied.
S. cerevisiae and
R. nigricans were good biosorbents at initial dye concentration of 50
mg/L, 1
g% (w/v) biomass loading and 29
±
1
°C.
R. nigricans adsorbed 90–96% dye in 15
min, at 20
°C and pH 6.0. The data showed an optimal fit to the Langmuir and Freundlich isotherms. The maximum uptake capacity (
Q
o
) for the selected dyes was in the range 112–204
mg/g biomass.
Colorectal cancer (CRC), which occurs at the junction of the rectum and sigmoid colon, is a common malignancy associated with poor prognosis and high mortality worldwide. The exopolysaccharide ...(EPS1-1), isolated from the fermentation broth of
(
), has been reported to possess anti-CRC properties. However, the metabolic alterations caused by azoxymethane (AOM) and dextran sulfate sodium (DSS) are still unknown.
In the present study, a mice colon cancer model was established by treatment with AOM/DSS. LC-MS/MS-based metabolomics studies were performed to analyze metabolic alterations at the tissue level. Partial least squares discriminant analysis (PLS-DA) was used to identify differentially expressed metabolites.
Nineteen distinct metabolites were identified that were associated with disruptions in the following pathways: biosynthesis of unsaturated fatty acids, pyrimidine metabolism, phenylalanine metabolism, fatty acid metabolism, folate biosynthesis, and inositol phosphate metabolism. Furthermore, six significantly altered metabolites were involved in these six pathways. Compared with the Model group, the expression of cytosine, deoxyuridine, 20-hydroxy-leukotriene E4, and L-homocysteic acid was lower, whereas that of 2-dehydro-3-deoxy-6-phospho-D-gluconic acid and hematoporphyrin was higher in the EPS1-1 group.
The results of multivariate statistical analysis demonstrate a promising application of the above metabolites by EPS1-1 in CRC therapy. Deeper understanding of the related mechanism warrants further investigation.
The aim of this study was to investigate the Cr(VI) biosorption potential of immobilized
Rhizopus nigricans and to screen a variety of non-toxic desorbing agents, in order to find out possible ...application in multiple sorption–desorption cycles. The biomass was immobilized by various mechanisms and evaluated for removal of Cr(VI) from aqueous solution, mechanical stability to desorbents, and reuse in successive cycles. The finely powdered biomass, entrapped in five different polymeric matrices viz. calcium alginate, polyvinyl alcohol (PVA), polyacrylamide, polyisoprene, and polysulfone was compared for biosorption efficiency and stability to desorbents. Physical immobilization to polyurethane foam and coir fiber was less efficient than polymer entrapment methods. Of the different combinations (%, w/v) of biomass dose compared for each matrix, 8% (calcium alginate), 6% (polyacrylamide and PVA), 12% (polyisoprene), and 10% (polysulfone) were found to be the optimum. The Cr sorption capacity (mg Cr/g sorbent) of all immobilized biomass was lesser than the native, powdered biomass. The Cr sorption capacity decreased in the order of free biomass (119.2)>polysulfone entrapped (101.5)>polyisoprene immobilized (98.76)>PVA immobilized (96.69)>calcium alginate entrapped
(84.29)>
polyacrylamide
(45.56)
, at 500 mg/l concentration of Cr(VI). The degree of mechanical stability and chemical resistance of the immobilized systems were in the order of polysulfone>polyisoprene>PVA>polyacrylamide>calcium alginate. The bound Cr(VI) could be eluted successfully using 0.01 N NaOH, NaHCO
3, and Na
2CO
3. The adsorption data for the native and the immobilized biomass was evaluated by the Freundlich isotherm model. The successive sorption–desorption studies employing polysulfone entrapped biomass indicated that the biomass beads could be regenerated and reused in more than 25 cycles and the regeneration efficiency was 75–78%.
The hazardous compound di-2-ethylhexyl phthalate (DEHP) is widely used as polyvinyl chloride plasticizer. The present research studied the fungal biodegradation of DEHP contained in blood and urine ...bags. Soil-plate method was used for fungal isolation from heavily plastic polluted soil using Martin’s and Sabouraud’s agar media, where DEHP was the sole carbon source. Isolated fungal species were identified morphologically according to Moubasher (Soil Fungi in Qatar and Arab Countries University of Qatar, Qatar The Center for Scientific and Research, 1993) as
Aspergillus nidulans, Aspergillus niger
and
Rhizopus nigricans
. DEHP concentrations were determined in 1 g of soil, urine bags and blood bags to be 0.92, 2.5 and 2.6 g/l, respectively. Samples of both bags (as a sole carbon source) were artificially inoculated with the isolated fungi and incubated for 20 days. As the time increased, the growth increased where
Rhizopus nigricans
obtained the highest dry weight in urine bags after 20 days of incubation, while
A. nidulans
had the highest dry weight in blood bags. Also, a sharp declining of initial pH (6.8) reached 4.7 in urine bags with
A. niger
growth, while reached 2.5 after
A. nidulans
growth in blood bags. DEHP% decreased as time increased indicating a continuous DEHP utilization by the three fungal species.
Aspergillus niger
was the most DEHP degrading fungal species in both bags. Scanning electron microscope examination showed an uniform plastic network in both bags before fungal treatment. While, a microporous network was observed on the plastic surfaces in both bags after fungal treatment due to DEHP utilization. The most DEHP metabolizing fungal species were further identified molecularly using internal transcribed spacer primers to be
Aspergillus niger
and
Aspergillus nidulans
with accession numbers MZ832174 and MT919276, respectively.
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In this study, the effect of antitumor and immune activities of extracellular polysaccharides (EPS) from Rhizopus nigricans Ehrenb were investigated using S180 bearing mice. The ...results revealed that EPS in the concentration range 50–1000μg/mL can inhibited S180 cell proliferation in a dose dependent manner. EPS at the highest dose of 1000μg/mL showed significantly antitumor activity against S180 with inhibition rate of 47.53%. However, EPS significantly simulated spleen lymphocytes in the concentration of 500μg/mL, and the increase proliferation ability showed a dose-dependent effect with EPS at the dose of 50–500μg/mL. In comparison with the control groups, the weights of tumor were declined and the inhibition rates of tumor were remarkably decreased in the treated groups. Pretreatment with EPS at the dose of 75mg/kg/day, the inhibition rate was decreased by 44.38% (P<0.05). EPS increased the concentrations of IL-2 and TNF-a. The pathological changes of model control group were very obvious. Meanwhile, the prophylactic administration of EPS could more efficiently inhibit the growth of S180 tumor than direct administration of EPS. EPS could prolong the survival period of S180 tumor bearing mice, and the doses 75mg/kg/day of EPS and combined with cyclophosphamide (20mg/kg/day) were 43.36% and 36.28% respectively compared to control groups (P<0.05). The results suggested EPS confirmed in vivo anti-tumor effects observed in vitro, and the mechanism of anti-tumor effect of EPS may be at least in part mediated by increased immune activity in host.
Grape rot is one of the major causes of degradation of many grape components and, thus, of deterioration in wine quality. In particular, the association of Botrytis cinerea with other, less visible, ...fungi frequently leads to the development of organoleptic defects in grapes and sometimes in wines. This study examines the nature of the volatile compounds responsible for mushroom, mossy, or earthy odors detected by gas chromatography-olfactometry in organic extracts of rotten grapes and musts. 2-Methylisoborneol, (-)-geosmin, 1-octen-3-one, 1-octen-3-ol, 2-octen-1-ol, and 2-heptanol were identified or tentatively identified. Their concentrations in musts were determined, and the impact of alcoholic fermentation by the yeast Saccharomyces cerevisiae was studied. The ability of fungi isolated from rotten grapes (Botrytis cinerea; Penicillium species including P. brevicompactum, P. expansum, P. miczynskii, P. pinophilum, P. purpurogenum, and P. thomii; Aspergillus section nigri; Rhizopus nigricans; and Coniothyrium sp.) to produce some of the identified compounds was evidenced.
•Effect of increased ambient solar UV-B supplemented with UV-B lamps was assessed for strawberry fruit quality.•The incidence of Colletotrichum truncatum as post harvest fungi was higher in ambient ...solar UV-B supplemented.•Changes in UV-B intensity did not promote effect on strawberry fruit production and physico-chemical parameters.•Under environmental conditions of increased UV-B radiation, the probability of post harvest loss by phytopathogens will be higher.
The effect of the UV-B radiation on the latent fungi infection in strawberry fruit, on plant production and on physico-chemical quality parameters of strawberry fruits during postharvest preservation was investigated. The experiments were conducted under field conditions in two seasons during 2012. The different UV-B treatments were: Ambient solar UV-B; Ambient solar UV-B reduced by 80% UV-B(−) and Ambient solar UV-B supplemented with UV-B lamps UV-B(+). An electronic modulation system was used to keep the increase on UV-B rate at constant levels throughout the day. The parameters evaluated were latent infection of fungi, dry matter of plants, physico-chemical attributes, color of the peel and fruit production. There was no significant difference among the irradiation treatments regarding the incidence of Rhizopus nigricans and Botrytis cinerea at both seasons. Independently on the season and the irradiation treatment, the incidence of R. nigricans was higher than the B. cinerea and this was considered the main postharvest fungi in the experiment. The incidence of Colletotrichum acutatum was limited to second season and it was higher on UV-B(+) treatment. The irradiation treatments had no influence on the dry matter, fruit production, the physico-chemical parameters and color. A strong correlation of both average temperature and precipitation on the incidence of R. nigricans and B. cinerea three weeks before harvesting was detected on both seasons using the Pearson correlation coefficients. The incidence of R. nigricans was positively correlated with precipitation and negatively correlated with average temperature. The inverse has been observed for B. cinerea. The results indicate that, on environmental conditions of a higher UV-B radiation, the probability of spoilage of strawberry fruit would be increased only by C. acutatum incidence.
► Ionic liquid is introduced into fungi whole-cell biocatalysis for the first time. ► Conversion is increased to 95% at 18g/L substrate and catalysis time shortened. ► Semi-continuous production is ...achieved in biphasic system with the recycle of IL. ► A simplified catalysis mechanism is proposed in IL-Aq biphasic system.
11α-Hydroxylation of 16α,17-epoxyprogesterone (EP) by Rhizopus nigricans is an essential step in the synthesis of many steroidal drugs, while low conversion of the biohydroxylation is a tough problem to be solved urgently in industry. Two ionic liquids (ILs) of BMImPF6 and BMImNTf2 were used in the biotransformation of EP by R. nigricans. The results indicated that the conversion carried out in BMImPF6-aqueous biphasic system was greatly increased to above 90% at 18g/L feeding concentration. A simplified mechanism was proposed to explain the improvement of the bioconversion in a biphasic ionic liquid aqueous system. Besides, successive three batches of bioconversion were carried out in the biphasic system with a total conversion of 87% at phase ratio 10 and 75% at phase ratio 5, respectively. Since recycling of the BMImPF6 is quite easy, there is a great potential for the application of ILs in fungi biotransformation to implement green production.
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