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1.
Chemosphere ; 239: 124806, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726521

RESUMO

Nitrobenzene (NB) is recalcitrant to microbial biodegradation due to the electron-deficient character of the nitro group (NO2-). Prior work has found that the reductant could enhance NB biodegradation by providing excess electron donors. However, the existing theory couldn't explain the increase-and-decrease pattern of the NB biodegradation rate with an increase in a reductant concentration. Our results suggest that the reductant affects NB biodegradation by two mechanisms: the available electron donors and the stimulation or inhibition of biomass growth, which are linked by a pseudo-first-order reaction kinetics. In addition, the results showed that directly inoculating the plain soil into the aquatic system and then allowing the synergistic effect of the organic reductant (ascorbic acid) and the substrate (peptone) enhance NB biodegradation. Employing the new method, 200 mg L-1 NB was transformed in 72 h. GC-MS analysis detected two novel intermediate metabolites, indicating that NB was degraded into aniline and further transformed into acetanilide and 9-octadecenamide before its mineralization. This study sheds light on how to exploit the synergistic effects of the availability of excess electron donors and biomass growth by controlling the reductant and a substrate in the right concentration range (e.g., ascorbic acid < 0.8 mgL-1 + peptone).


Assuntos
Ácido Ascórbico/química , Biodegradação Ambiental , Nitrobenzenos/metabolismo , Peptonas/química , Poluentes do Solo/análise , Solo/química , Acetanilidas/síntese química , Compostos de Anilina/síntese química , Estudos de Viabilidade , Cinética , Ácidos Oleicos/síntese química
2.
Se Pu ; 37(11): 1157-1161, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642267

RESUMO

A method using ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of nine B vitamins in peptone. The samples were extracted with water. The analytes were separated on a Syncronis C18 column (100 mm×2.1 mm, 1.7 µm). The nine B vitamins were detected by ESI-MS/MS under the multiple reaction monitoring (MRM) mode, and the analysis was completed in 8 min. Quantification analysis was performed by using the external standard method. The correlation coefficients (R2) of the nine B vitamins in their linear ranges were greater than 0.999. The limits of detection were 0.09-1.67 µg/L. The relative standard deviations of the method were less than 3% (n=6). The mean recoveries of the nine B vitamins were 80.2%-103.9% at different spiked levels. The method is simple, accurate and sensitive, and is suitable for the determination of the nine B vitamins in peptone.


Assuntos
Peptonas/química , Complexo Vitamínico B/análise , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem
3.
Poult Sci ; 98(1): 393-397, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30125007

RESUMO

In 2016, USDA-Food Safety and Inspection Service began using a neutralizing buffered peptone water (nBPW) to rinse broiler carcasses for Salmonella and Campylobacter performance standard testing. The nBPW contains standard buffered peptone water (BPW) with compounds to neutralize residual antimicrobials that may be transferred from the carcass to the sample rinsate. However, a direct comparison of nBPW and BPW on carcasses commercially treated with antimicrobials has not been conducted. On 3 replicate days in a commercial broiler processing plant, an immersion chilling biomap using whole carcass rinse samples taken prior to any chilling treatment (30), after pre-chill treatment (30), after primary chill (30), after secondary chill (30), after post-chill treatment (50), and after post-chill treatment without the pre-chill treatment (49) were tested. Carcasses were rinsed with either BPW (without neutralizer) or nBPW. Rinsates were sampled for Salmonella and Campylobacter prevalence and both Enterobacteriaceae (EB) prevalence and counts. No significant differences were observed between sampling sites or rinse media for Salmonella due to an overall low prevalence (4 positive/219 samples). Campylobacter prevalence significantly decreased from prior to chilling (93%) to after all chilling steps (47%) as anticipated (P < 0.0001); however, overall significantly fewer Campylobacter positive carcasses were detected when nBPW was used (55%) in comparison to BPW (70%, P = 0.0258). Both EB prevalence and counts significantly decreased (both P < 0.0001) from prior to chilling (100%, 2.35 log10 CFU/mL) through after all chilling steps (52%, 0.47 log10 CFU/mL). The use of nBPW versus BPW did not impact EB prevalence; however, samples rinsed with nBPW had significantly higher overall counts (1.26 vs. 1.00 log10 CFU/mL, P = 0.0134). The results from this study indicate that the use of a PAA pre-chill treatment did not significantly impact bacteria recovery following all chilling steps. The use of nBPW was effective in neutralizing residual PAA in carcass rinsates when sampling for EB counts; however, nBPW may lessen the ability to detect Campylobacter in these same samples.


Assuntos
Campylobacter/isolamento & purificação , Enterobacteriaceae/isolamento & purificação , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Salmonella/isolamento & purificação , Animais , Anti-Infecciosos/química , Tampões (Química) , Galinhas , Carne/microbiologia , Peptonas/química , Ácido Peracético/química , Água
4.
Int J Biol Macromol ; 124: 1186-1196, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30521923

RESUMO

To contribute towards effective exploitation and utilization of natural antioxidants, response surface methodology (RSM) was employed to optimize the medium composition for the production of exopolysaccharides from the medicinal mushroom Ganoderma lingzhi (GLEPS). An optimal medium for GLEPS production was gave through Plackett-Burman design, path of steepest ascent, and Box-Behnken design as follows: glucose (59.62 g/L), yeast extract (10.03 g/L), CaCO3 (0.2 g/L), thiamine (45.13 mg/L), KH2PO4 (1.0 g/L), peptone (1.5 g/L), Tween 80 (10.26 mL/L), ZnSO4 (0.3 g/L), mannitol (1.5 g/L), MgSO4 (0.5 g/L), and aspartate (8.86 g/L). The GLEPS yield obtained was 3.57 ±â€¯0.21 g/L-3.16-fold higher than that produced in basal medium alone. The resulting GLEPS rich in uronic acid, d-mannose, l-rhamnose, and d-glucose, was a heteropolysaccharide with high-molecular weights (475,000 kDa and 21.6 kDa, 87.97%). It was demonstrated that the GLEPS with higher carbohydrate and uronic acid contents exhibited strong in vitro antioxidant activities via radical scavenging, reductive capacity, and chelation of transition metal catalysis. These findings indicated that RSM is an efficient tool to predict the composition of culture medium required for maximizing GLEPS yield, and GLEPS had potent antioxidant activities and could be explored as a novel natural antioxidant in functional food or medicine.


Assuntos
Antioxidantes/química , Meios de Cultura/química , Polissacarídeos Fúngicos/química , Ganoderma/química , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Ácido Aspártico/química , Ácido Aspártico/farmacologia , Benzotiazóis/antagonistas & inibidores , Benzotiazóis/química , Compostos de Bifenilo/antagonistas & inibidores , Compostos de Bifenilo/química , Meios de Cultura/farmacologia , Análise Fatorial , Polissacarídeos Fúngicos/biossíntese , Polissacarídeos Fúngicos/isolamento & purificação , Ganoderma/efeitos dos fármacos , Ganoderma/metabolismo , Glucose/química , Glucose/farmacologia , Radical Hidroxila/antagonistas & inibidores , Radical Hidroxila/química , Manitol/química , Manitol/farmacologia , Manose/química , Manose/farmacologia , Peptonas/química , Peptonas/farmacologia , Picratos/antagonistas & inibidores , Picratos/química , Polissorbatos/química , Polissorbatos/farmacologia , Ramnose/química , Ramnose/farmacologia , Ácidos Sulfônicos/antagonistas & inibidores , Ácidos Sulfônicos/química , Superóxidos/antagonistas & inibidores , Superóxidos/química , Tiamina/química , Tiamina/farmacologia
5.
J Biotechnol ; 271: 56-62, 2018 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-29476806

RESUMO

Peptones are accepted as one of the most favourable nitrogen sources supporting pigment synthesis in Monascus purpureus. The present study was performed to test the feasibility of chicken feather peptone (CFP) as nitrogen source for pigment production from M. purpureus ATCC16365. CFP was compared with fish peptone (FP) and protease peptone (PP) in order to elucidate its effectiveness on pigment production. CFP was prepared from waste feathers using hydrolysis (KOH) and neutralization (H2SO4) methods. The protein content of CFP was determined as 67.2 g/100 g. Optimal concentrations of CFP and glucose for pigment production were determined as 3 and 20 g/L, respectively. A medium pH of 5.5 and an incubation period of 7-days were found to be more favourable for pigment production. In CFP, PP and FP media, yellow pigment absorbances were 2.819, 2.870 and 2.831, red pigment absorbances were 2.709, 2.304 and 2.748, and orange pigment absorbances were 2.643, 2.132 and 2.743, respectively. Sugar consumption and mycelia growth showed the similar trends in CFP, FP and PP media. This study indicates that the peptone from chicken feathers may be a good nutritional substrate for pigment production from M. purpureus.


Assuntos
Plumas/química , Monascus/crescimento & desenvolvimento , Nitrogênio/química , Peptonas/química , Pigmentos Biológicos/metabolismo , Animais , Galinhas , Estudos de Viabilidade , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Monascus/metabolismo , Pigmentação
6.
Exp Cell Res ; 360(2): 163-170, 2017 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-28887025

RESUMO

Gold nanoparticles have been investigated extensively for their molecular mechanisms of action and anticancer potential. We report a novel, tubulin-targeted antiproliferative mechanism of action of tryptone-stabilized gold nanoparticles (TsAuNPs). TsAuNPs, synthesized using HAuCl4·3H2O and tryptone and characterized by a variety of spectroscopic methods and transmission electron microscopy, were found to be inhibitory to viability of human pancreatic (PANC-1), cervical (HeLa), and breast (MDA-MB-231) cancer cell lines in a concentration-dependent manner, with highest efficacy against PANC-1 cells. The particles strongly inhibited the clonogenic propagation of PANC-1 cells. TsAuNPs-mediated inhibition of cell viability involved an unusual mode of cell cycle arrest (arrest at both G0/G1 phase and S-phase) followed by apoptosis. In vitro, TsAuNPs bound purified tubulin, competitively inhibited anilinonaphthalene sulfonate binding to tubulin, and suppressed tubulin assembly. In cells, tubulin-TsAuNPs interactions were manifested as a disrupted microtubule network, defective reassembly of cold-disassembled microtubules, and induction of tubulin acetylation. Our data indicate that TsAuNPs inhibit cell viability by inducing differential cell cycle arrest possibly through disrupted dynamicity of cellular microtubules.


Assuntos
Ciclo Celular/efeitos dos fármacos , Ouro/química , Nanopartículas Metálicas/química , Peptonas/química , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Estabilidade de Medicamentos , Ouro/farmacologia , Células HeLa , Humanos , Camundongos , Terapia de Alvo Molecular/métodos , Células NIH 3T3 , Peptonas/farmacologia , Tubulina (Proteína)/metabolismo
7.
Molecules ; 22(6)2017 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-28608830

RESUMO

Diketopiperazines can be generated by non-enzymatic cyclization of linear dipeptides at extreme temperature or pH, and the complex medium used to culture bacteria and fungi including phytone peptone and trypticase peptone, can also produce cyclic peptides by heat sterilization. As a result, it is not always clear if many diketopiperazines reported in the literature are artifacts formed by the different complex media used in microorganism growth. An ideal method for analysis of these compounds should identify whether they are either synthesized de novo from the products of primary metabolism and deliver true diketopiperazines. A simple defined medium (X. fastidiosa medium or XFM) containing a single carbon source and no preformed amino acids has emerged as a method with a particularly high potential for the grown of X. fastidiosa and to produce genuine natural products. In this work, we identified a range of diketopiperazines from X. fastidiosa 9a5c growth in XFM, using Ultra-Fast Liquid Chromatography coupled with mass spectrometry. Diketopiperazines are reported for the first time from X. fastidiosa, which is responsible for citrus variegated chlorosis. We also report here fatty acids from X. fastidiosa, which were not biologically active as diffusible signals, and the role of diketopiperazines in signal transduction still remains unknown.


Assuntos
Dicetopiperazinas/farmacologia , Peptonas/química , Xylella/efeitos dos fármacos , Carbono/química , Caseínas/química , Cromatografia Líquida , Dicetopiperazinas/síntese química , Dicetopiperazinas/química , Peptonas/síntese química , Peptonas/farmacologia , Hidrolisados de Proteína/química , Espectrometria de Massas por Ionização por Electrospray , Xylella/crescimento & desenvolvimento
8.
Bioengineered ; 8(6): 693-699, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-28471292

RESUMO

Cold-adapted superoxide dismutase (SOD) with higher catalytic activity at lower temperature has great amount of applications in many aspects as an industrial enzyme. The application of recombinant enzyme in gene engineering and microbial fermentation technology is an effective way to obtain high-yield product. In this study, to obtain the recombinant SOD in E. coli (rPsSOD) with the highest activity, the Box-Behnken design was first applied to optimize the important parameters (lactose, tryptone and Tween-80) affecting the activity of rPsSOD. The results showed that the optimal fermentation conditions were Tween-80 (0.047%), tryptone (6.16 g/L), lactose (11.38 g/L). The activity of rPsSOD was 71.86 U/mg (1.54 times) as compared with non-optimized conditions. Such an improved production will facilitate the application of the cold-adapted rPsSOD.


Assuntos
Escherichia coli/enzimologia , Superóxido Dismutase/metabolismo , Temperatura Baixa , Meios de Cultura , Fermentação/fisiologia , Lactose/química , Peptonas/química , Polissorbatos/química
9.
Sci Rep ; 7: 42129, 2017 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-28195138

RESUMO

In this present study, a newly isolated strain, Streptomyces sp. NEAE-H, capable of producing high amount of black extracellular melanin pigment on peptone-yeast extract iron agar and identified as Streptomyces glaucescens NEAE-H. Plackett-Burman statistical design was conducted for initial screening of 17 independent (assigned) variables for their significances on melanin pigment production by Streptomyces glaucescens NEAE-H. The most significant factors affecting melanin production are incubation period, protease-peptone and ferric ammonium citrate. The levels of these significant variables and their interaction effects were optimized by using face-centered central composite design. The maximum melanin production (31.650 µg/0.1 ml) and tyrosinase activity (6089.10 U/ml) were achieved in the central point runs under the conditions of incubation period (6 days), protease-peptone (5 g/L) and ferric ammonium citrate (0.5 g/L). Melanin pigment was recovered by acid-treatment. Higher absorption of the purified melanin pigment was observed in the UV region at 250 nm. It appeared to have defined small spheres by scanning electron microscopy imaging. The maximum melanin yield was 350 mg dry wt/L of production medium. In vitro anticancer activity of melanin pigment was assayed against skin cancer cell line using MTT assay. The IC50 value was 16.34 ± 1.31 µg/ml for melanin and 8.8 ± 0.5 µg/ml for standard 5-fluorouracil.


Assuntos
Antineoplásicos/metabolismo , Antioxidantes/metabolismo , Melaninas/biossíntese , RNA Ribossômico 16S/genética , Streptomyces/metabolismo , Ágar/química , Ágar/farmacologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Meios de Cultura/química , Meios de Cultura/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Fermentação , Humanos , Melaninas/isolamento & purificação , Melaninas/farmacologia , Peptonas/química , Peptonas/farmacologia , Filogenia , Streptomyces/classificação , Streptomyces/efeitos dos fármacos , Streptomyces/genética
10.
Colloids Surf B Biointerfaces ; 151: 47-57, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-27974276

RESUMO

This work demonstrates the use of bacteriophage conjugated magnetic particles (Fe3O4) for the rapid capturing and isolation of Escherichia coli. The investigation of T4 bacteriophage adsorption to silane functionalised Fe3O4 with amine (NH2), carboxylic (COOH) and methyl (CH3) surface functional groups reveals the domination of net electrostatic and hydrophobic interactions in governing bacteriophage adsorption. The bare Fe3O4 and Fe3O4-NH2 with high T4 loading captured 3-fold more E. coli (∼70% capturing efficiency) compared to the low loading T4 on Fe3O4-COOH, suggesting the significance of T4 loading in E. coli capturing efficiency. Importantly, it is further revealed that E. coli capture is highly dependent on the incubation temperature and the presence of tryptone in the media. Effective E. coli capturing only occurs at 37°C in tryptone-containing media with the absence of either conditions resulted in poor bacteria capture. The incubation temperature dictates the capturing ability of Fe3O4/T4, whereby T4 and E. coli need to establish an irreversible binding that occurred at 37°C. The presence of tryptophan-rich tryptone in the suspending media was also critical, as shown by a 3-fold increase in E. coli capture efficiency of Fe3O4/T4 in tryptone-containing media compared to that in tryptone-free media. This highlights for the first time that successful bacteria capturing requires not only an optimum tailoring of the particle's surface physicochemical properties for favourable bacteriophage loading, but also an in-depth understanding of how factors, such as temperature and solution chemistry influence the subsequent bacteriophage-bacteria interactions.


Assuntos
Bacteriófago T4/fisiologia , Escherichia coli/virologia , Nanopartículas de Magnetita/química , Peptonas/química , Adsorção , Bacteriófago T4/química , Simulação por Computador , Escherichia coli/efeitos dos fármacos , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Luz , Magnetismo , Microscopia Eletrônica de Transmissão , Espalhamento de Radiação , Silanos/química , Eletricidade Estática , Propriedades de Superfície , Temperatura Ambiente
11.
Methods Mol Biol ; 1512: 9-18, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27885594

RESUMO

The recovery of Campylobacter species from food and environmental sources is challenging due to the slow growth of these bacteria and the need to suppress competing organisms during the isolation procedures. The addition of multiple selective antimicrobials to growth media can negatively impact recovery of some Campylobacter spp. Here, we describe our current method for the isolation of thermotolerant Campylobacter species, mainly C. jejuni and C. coli, from food and environmental samples. We emphasize the use of membrane filtration during plating for the specific isolation of Campylobacter spp. and a reduced use of antimicrobial supplements throughout the whole isolation process.


Assuntos
Proteínas de Bactérias/genética , Microbiologia de Alimentos , Carne/microbiologia , Leite/microbiologia , Microbiologia da Água , Adaptação Fisiológica , Amidoidrolases/genética , Animais , Aspartato Quinase/genética , Campylobacter coli , Campylobacter jejuni , Galinhas , Contagem de Colônia Microbiana , Meios de Cultura/química , Primers do DNA/síntese química , Primers do DNA/metabolismo , Filtração/métodos , Expressão Gênica , Temperatura Alta , Reação em Cadeia da Polimerase Multiplex , Peptonas/química , RNA Ribossômico 16S/genética
12.
PLoS One ; 11(12): e0167981, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27992459

RESUMO

Pectic-Oligosaccharides (POS) have a growing potential in food and feed industries. To satisfy the demand of worldwide markets from POS and avoid the shortcomings of currently applied methodologies encountered in their preparation, the present study highlights a novel robust approach for POS biosynthesis. In the current approach, Aspergillus sp.section Flavi strain EGY1 DSM 101520 was grown on citrus pectin-based medium as a core POS production medium. POS' levels accumulated in the fungal fermentation broth were optimized through a three step sequential statistical mathematical methodology; Plackett-Burman design (PBD), Box-Behnken design (BBD) and canonical analysis. Three key determinants namely citrus pectin, peptone and NaH2PO4 were pointed out by PBD to impose significant consequences (P<0.05) on the process outcome (POS' levels). Optimal levels of these key determinants along with maximal of POS' levels were set by BBD and canonical analysis to be 2.28% (w/v) citrus pectin, 0.026% (w/v) peptone and 0.28% (w/v) NaH2PO4 to achieve a net amount of 1.3 g POS /2.28 g citrus pectin. Through this approach, a yield of 57% (w/w) POS of the total citrus pectin was obtained after 24 h of fungal growth on optimized citrus pectin-based medium. A fold enhancement of 13 times in POS' levels released in the fermentation fungal broth was realized by the end of the optimization strategy. This novel robust approach is considered a new insight towards POS biosynthesis via efficient, rapid and non-cumbersome procedure. To the best of authors' knowledge, the present work is the first article underlining detailed POS production from the fermentation broth of a fungus growing on citrus pectin-based medium.


Assuntos
Aspergillus/crescimento & desenvolvimento , Oligossacarídeos/biossíntese , Pectinas/química , Aspergillus/metabolismo , Metabolismo dos Carboidratos , Fermentação , Indústria Alimentícia , Concentração de Íons de Hidrogênio , Peptonas/química , Fosfatos/química
13.
Int J Biol Macromol ; 92: 1113-1122, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27519291

RESUMO

Endoinulinase is an inulolytic enzyme which is used for the production of fructooligosaccharides from inulin. A new endoinulinase producing fungal strain BGPUP6 was identified as Aspergillus tritici on the basis of its molecular characterization. Response surface methodology was used to optimize the endoinulinase production at shake-flask level from Aspergillus tritici BGPUP6 using raw Asparagus inulin as carbon source. Four independent variables (raw inulin, 2-4%; peptone, 0.3-0.7%; (NH4)H2PO4, 0.3-0.7% and pH, 4.5-6.5) were selected for the study based on the CCRD model of RSM. The other media supplements (FeSO4·7H2O, 0.001%; MgSO4·7H2O, 0.05% and KCl, 0.02%) were kept constant in the production medium, throughout the study. Endoinulinase production and biomass yield were selected as dependent responses. The optimal combination of media ingredients obtained from the study was 3% raw inulin, 0.5% peptone, 0.5% (NH4)H2PO4 and pH 5.5. Using the optimized media constituents, maximum endoinulinase production (25.01 IU/mL) and biomass yield (0.514g dry weight/50 mL) obtained were in good agreement with the predicted values. Crude enzyme produced was also used for the hydrolysis of inulin. The hydrolysate showed the presence of a mixture of fructooligosaccharides with varied degree of polymerization. This is the first report on the production of an endoinulinase from Aspergillus tritici.


Assuntos
Aspergillus/metabolismo , Proteínas Fúngicas/biossíntese , Glicosídeo Hidrolases/biossíntese , Microbiologia Industrial , Inulina/química , Oligossacarídeos/biossíntese , Asparagus (Planta)/química , Biomassa , Análise Fatorial , Proteínas Fúngicas/química , Proteínas Fúngicas/isolamento & purificação , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/isolamento & purificação , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Oligossacarídeos/isolamento & purificação , Peptonas/química , Fosfatos/química , Especificidade por Substrato
14.
Bioresour Technol ; 218: 410-7, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27393831

RESUMO

In this study, lactic acid fermentation by Rhizopus oryzae was investigated using the two different fermentation strategies of one-step fermentation (OSF) and conventional fermentation (CF). Compared to CF, OSF reduced the demurrage of the production process and increased the production of lactic acid. However, the qp was significantly lower than during CF. Based on analysis of µ, qs and qp, a novel modified OSF strategy was proposed. This strategy aimed to achieve a high final concentration of lactic acid, and a high qp by R. oryzae. In this strategy, the maximum lactic acid concentration and productivity of the lactic acid production stage reached 158g/l and 5.45g/(lh), which were 177% and 366% higher, respectively, than the best results from CF. Importantly, the qp and yield did not decrease. This strategy is a convenient and economical method for l-lactic acid fermentation by R. oryzae.


Assuntos
Fermentação , Ácido Láctico/biossíntese , Rhizopus/metabolismo , Reatores Biológicos , Cromatografia Líquida de Alta Pressão , Meios de Cultura , Microbiologia Industrial , Cinética , Nitrogênio/química , Peptonas/química , Temperatura Ambiente
15.
Environ Pollut ; 213: 299-307, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26925752

RESUMO

The effects of four types of dissolved organic matters (DOM) on the bioconcentration of perfluoroalkyl substances (PFASs) in Chironomus plumosus larvae have been studied. The PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA). The DOM included humic acid (HA), fulvic acid (FA), tannic acid (TA), and a protein, peptone (PEP), and their concentrations ranged from 0 to 50 mg L(-1). The results showed that, upon bioconcentration equilibrium, the body burdens of longer perfluoroalkyl chain PFASs (PFOS, PFDA, PFUnA and PFDoA) decreased with PEP and HA concentrations while increased with FA and TA concentrations. When FA and TA concentrations increased from 0 to 50 mg L(-1), body burdens of these PFASs increased by 7.5%-148.8% and 5.7%-37.1%, respectively. However, the DOM had no significant impact on the body burdens of shorter perfluoroalkyl chain PFASs (PFOA and PFNA). All of the four types of DOM lowered not only the uptake rate constants (ku) of PFASs due to the decrease of freely dissolved PFAS concentrations, but also the elimination rate constants (ke) due to the inhibition effect of DOM on the PFAS elimination from the larvae. The reduction in the two constants varied with both DOM and PFAS types. In the presence of PEP and HA with larger molecular weights, the ku values decreased more than ke, leading to the decreased body burdens of longer perfluoroalkyl chain PFASs. As for FA and TA with smaller molecular weights, the ke values decreased more than ku, resulting in increased body burdens of longer perfluoroalkyl chain PFASs. This study suggests that the effects of DOM on PFAS bioconcentration depend not only on the concentration but also on the molecule weight of DOM, which should be considered in the bioavailability assessment of PFASs.


Assuntos
Chironomidae/metabolismo , Fluorcarbonetos/farmacocinética , Substâncias Húmicas , Poluentes Químicos da Água/farmacocinética , Ácidos Alcanossulfônicos/química , Ácidos Alcanossulfônicos/farmacocinética , Animais , Benzopiranos/química , Carga Corporal (Radioterapia) , Caprilatos/química , Caprilatos/farmacocinética , Ácidos Decanoicos/química , Ácidos Decanoicos/farmacocinética , Fluorcarbonetos/química , Cadeia Alimentar , Larva/metabolismo , Peptonas/química , Taninos/química , Água , Poluentes Químicos da Água/química
16.
J Hazard Mater ; 302: 1-9, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26448488

RESUMO

Iron sulfide (FeS) nanoparticles have been recognized as effective scavengers for multi-valent metal ions. However, the aggregation of FeS nanoparticles in aqueous solution greatly restricts their application in real work. Herein, different biomaterial-FeS nanoparticles were developed for the in-situ immobilization of uranium(VI) in radioactive waste management. TEM images suggested that sodium carboxymethyl cellulose (CMC) and gelatin can effectively suppress the aggregation of FeS nanoparticles in aqueous solutions. The resulting CMC-FeS and gelatin-FeS were stable in aqueous solutions and showed high adsorption capacity for U(VI). Specially, gelatin-FeS showed the best performance in U(VI) adsorption-reduction immobilization under experimental conditions. The maximum enrichment capacity of U(VI) on CMC-FeS and gelatin-FeS at pH 5.0 and 20 °C achieved to ∼430 and ∼556 mg/g, respectively. Additionally, gelatin-FeS and CMC-FeS nanoparticles presented excellent tolerance to environmental salinity. The immobilized U(VI) on the surfaces of CMC-FeS and gelatin-FeS remained stable more than one year. These findings highlight the possibility of using ggelatin-FeS for efficient immobilization of U(VI) from radioactive wastewater.


Assuntos
Biomassa , Compostos Ferrosos/química , Nanopartículas/química , Urânio/química , Poluentes Radioativos da Água/química , Animais , Carboximetilcelulose Sódica/química , Bovinos , Ciclodextrinas/química , Gelatina/química , Glucose/química , Cinética , Microscopia Eletrônica de Transmissão , Peptonas/química , Salinidade , Termodinâmica , Extratos de Tecidos/química , Leveduras
17.
Waste Manag ; 48: 513-520, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26459187

RESUMO

The production of carboxymethyl cellulase (CMCase) by Bacillus halodurans IND18 under solid substrate fermentation (SSF) using cow dung was optimized through two level full factorial design and second order response surface methodology (RSM). The central composite design (CCD) was employed to optimize the vital fermentation parameters, such as pH of the substrate, concentration of nitrogen source (peptone) and ion (sodium dihydrogen phosphate) sources in medium for achieving higher enzyme production. The optimum medium composition was found to be 1.46% (w/w) peptone, 0.095% (w/w) sodium dihydrogen phosphate and pH 8.0. The model prediction of 4210IU/g enzyme activity at optimum conditions was verified experimentally as 4140IU/g. The enzyme was active over a broad temperature range (40-60±1°C) and pH (7.0-9.0) with maximal activity at 60±1°C and pH 8.0. This study demonstrated the potential of cow dung as novel substrate for CMCase production.


Assuntos
Bacillus/enzimologia , Celulase/química , Esterco , Agricultura/métodos , Animais , Bacillus cereus/enzimologia , Bovinos , Poluentes Ambientais/química , Fermentação , Resíduos de Alimentos , Concentração de Íons de Hidrogênio , Microbiologia Industrial/métodos , Modelos Estatísticos , Nitrogênio/química , Oryza , Peptonas/química , Pseudoalteromonas/enzimologia , Eliminação de Resíduos/métodos , Shewanella/enzimologia , Temperatura Ambiente , Xanthomonas/enzimologia
18.
Poult Sci ; 94(12): 3048-51, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26467004

RESUMO

Salmonella is a human pathogen that can accompany live broilers to the slaughter plant, contaminating fully processed carcasses. Feed is one potential source of Salmonella to growing broilers. Monitoring feed for the presence of Salmonella is part of good agricultural practice. The first step in culturing feed for Salmonella (which may be at low numbers and sub-lethally stressed) is to add it to a pre-enrichment broth which is incubated for 24 h. During the course of pre-enrichment, extraneous bacteria metabolize carbohydrates in some feed and excrete acidic byproducts, causing the pH to drop dramatically. An acidic pre-enrichment pH can injure or kill Salmonella resulting in a failure to detect, even if it is present and available to infect chickens. The objective of this study was to test an array of buffering chemistries to prevent formation of an injurious acidic environment during pre-enrichment of feed in peptone water. Five grams of feed were added to 45 mL of peptone water buffered with carbonate, Tris pH 8, and phosphate buffering ingredients individually and in combination. Feed was subjected to a pre-enrichment at 35°C for 24 h; pH was measured at 0, 18, and 24 h. Standard phosphate buffering ingredients at concentrations up to 4 times the normal formulation were unable to fully prevent acidic conditions. Likewise, carbonate and Tris pH 8 were not fully effective. The combination of phosphate, carbonate, and Tris pH 8 was the most effective buffer tested. It is recommended that a highly buffered pre-enrichment broth be used to examine feed for the presence of Salmonella.


Assuntos
Ração Animal/microbiologia , Técnicas Bacteriológicas/métodos , Peptonas/química , Salmonella/crescimento & desenvolvimento , Água/química , Ração Animal/análise , Animais , Tampões (Química) , Galinhas/microbiologia , Dieta/veterinária , Concentração de Íons de Hidrogênio , Salmonella/isolamento & purificação
19.
Bioresour Technol ; 198: 533-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26432057

RESUMO

In this study, a moderate thermophile Clostridium thermobutyricum is shown to ferment the sugars in sweet sorghum juice treated with invertase and supplemented with tryptone (10 g L(-1)) and yeast extract (10 g L(-1)) at 50°C to 44 g L(-1) butyrate at a calculated highest volumetric productivity of 1.45 g L(-1)h(-1) (molar butyrate yield of 0.85 based on sugars fermented). This volumetric productivity is among the highest reported for batch fermentations. Sugars from acid and enzyme-treated sweet sorghum bagasse were also fermented to butyrate by this organism with a molar yield of 0.81 (based on the amount of cellulose and hemicellulose). By combining the results from juice and bagasse, the calculated yield of butyric acid is approximately 90 kg per tonne of fresh sweet sorghum stalk. This study demonstrates that C. thermobutyricum can be an effective microbial biocatalyst for production of bio-based butyrate from renewable feedstocks at 50°C.


Assuntos
Biotecnologia/métodos , Ácido Butírico/metabolismo , Clostridium/metabolismo , Sorghum/metabolismo , Metabolismo dos Carboidratos , Celulose/química , Celulose/metabolismo , Fermentação , Peptonas/química , Polissacarídeos/metabolismo , Sorghum/química , beta-Frutofuranosidase/metabolismo
20.
Int J Food Microbiol ; 214: 109-115, 2015 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-26267889

RESUMO

This study evaluated the effects of changing the composition of the pre-enrichment medium buffered peptone water (BPW) on the growth of stressed and unstressed Gram-negative foodborne pathogens in a one-broth enrichment strategy. BPW supplemented with an available iron source and sodium pyruvate, along with low levels of 8-hydroxyquinoline and sodium deoxycholate (BPW-S) improved the recovery of desiccated Cronobacter spp. from powdered infant formula. Growth of Salmonella and STEC was comparable in all BPW variants tested for different food matrices. In products with high levels of Gram-negative background flora (e.g. sprouts), the target organisms could not be reliably detected by PCR in any of the BPW variants tested unless the initial level exceeded 10(3) cfu/10 g of sprouts. Based on these results we suggest BPW-S for a one-broth enrichment strategy of stressed Gram-negative foodborne pathogens from dry products. However, a one-broth enrichment strategy based on BPW variants tested in this evaluation is not recommended for produce with a high level of Gram-negative background flora due to very high detection limits.


Assuntos
Meios de Cultura/química , Microbiologia de Alimentos/métodos , Fórmulas Infantis/microbiologia , Salmonella/isolamento & purificação , Ácido Desoxicólico/química , Humanos , Lactente , Oxiquinolina/química , Peptonas/química , Reação em Cadeia da Polimerase , Ácido Pirúvico/química , Salmonella/crescimento & desenvolvimento , Água
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