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1.
Int J Biol Macromol ; 160: 446-455, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32479940

RESUMEN

In order to exploit an abundant and cheap carbon source for poly(3-hydroxybutyrate) (PHB) production, the rice husk was pretreated with dilute sulfuric acid and steam flash-explosion to enhance the enzymatic saccharification. The yield of reducing sugars of pretreated rice husk hydrolysate came up to 266.5 mg/g rice husk, much higher than that of untreated rice husk hydrolysate (72.67 mg/g rice husk). This result indicated that the pretreatment can significantly enhance the yield of reducing sugars. Then the hydrolysate was used as a sole carbon source for PHB production by using Cupriavidus necator. Response surface method was used to optimize the fermentation conditions. Under optimum fermentation conditions (carbon source, 31.81 gL-1; nitrogen source, 1.8 gL-1; pH-value, 7.0; temperature, 27.1 °C), the PHB yield was 5.0 gL-1, which was in good agreement with the predicted value.


Asunto(s)
Ácido 3-Hidroxibutírico/metabolismo , Hidroxibutiratos/metabolismo , Oryza/metabolismo , Poliésteres/metabolismo , Carbono/metabolismo , Cupriavidus necator/metabolismo , Explosiones , Fermentación/fisiología , Hidrólisis , Vapor , Azúcares/metabolismo , Ácidos Sulfúricos/metabolismo
2.
Genes (Basel) ; 11(6)2020 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-32560106

RESUMEN

Yeast biomass is recycled in the process of bioethanol production using treatment with dilute sulphuric acid to control the bacterial population. This treatment can lead to loss of cell viability, with consequences on the fermentation yield. Thus, the aim of this study was to define the functional cellular responses to inorganic acid stress. Saccharomyces cerevisiae strains with mutation in several signalling pathways, as well as cells expressing pH-sensitive GFP derivative ratiometric pHluorin, were tested for cell survival and cytosolic pH (pHc) variation during exposure to low external pH (pHex). Mutants in calcium signalling and proton extrusion were transiently sensitive to low pHex, while the CWI slt2Δ mutant lost viability. Rescue of this mutant was observed when cells were exposed to extreme low pHex or glucose starvation and was dependent on the induced reduction of pHc. Therefore, a lowered pHc leads to a complete growth arrest, which protects the cells from lethal stress and keeps cells alive. Cytosolic pH is thus a signal that directs the growth stress-tolerance trade-off in yeast. A regulatory model was proposed to explain this mechanism, indicating the impairment of glucan synthesis as the primary cause of low pHex sensitivity.


Asunto(s)
Ácidos/metabolismo , Saccharomyces cerevisiae/genética , Estrés Fisiológico/genética , Ácidos Sulfúricos/metabolismo , Ácidos/efectos adversos , Señalización del Calcio/genética , Metabolismo de los Hidratos de Carbono/genética , Supervivencia Celular/genética , Pared Celular/metabolismo , Citosol/metabolismo , Etanol/metabolismo , Fermentación/genética , Concentración de Iones de Hidrógeno , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Transducción de Señal/genética , Ácidos Sulfúricos/efectos adversos
3.
J Agric Food Chem ; 68(15): 4325-4334, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32208655

RESUMEN

As emerging alternatives of legacy perfluoroalkyl substances, 6:2 fluorotelomer sulfonate (6:2 FTS), 6:2 chlorinated polyfluoroalkyl ether sulfonates (6:2 Cl-PFESA), and perfluorophosphinates (C6/C6 and C8/C8 PFPiAs) are supposed to be partitioned to soil and highly persistent in the environment. The uptake of novel per- and polyfluoroalkyl substances (PFASs) by plants represents a potential pathway for their transfer in the food chain. In this study, the bioavailability of these four novel PFASs in soil and the bioaccumulation characteristics in greenhouse-grown wheat (Triticum aestivum L.), maize (Zea mays L.), soybean (Glycine max L. Merrill), and pumpkin (Cucurbita maxima L.) were investigated. The results indicated that these novel PFASs with higher hydrophobicity were more easily sequestrated in soil, and the fractions extracted by methanol could well describe their bioavailability, which could be stimulated by low-molecular-weight organic acids at rhizospheric concentrations. A negative relationship was found between root soil concentration factors (RSCFs) and hydrophobicity (log Kow) of the target PFASs. This correlation was also found in the translocation factors (TF) from roots to shoots. Furthermore, the uptake and transfer of the target PFASs were regulated by the protein contents in plant roots and shoots.


Asunto(s)
Productos Agrícolas/química , Fluoruros/química , Hidrocarburos Clorados/química , Contaminantes del Suelo/química , Suelo/química , Ácidos Sulfúricos/química , Bioacumulación , Disponibilidad Biológica , Productos Agrícolas/metabolismo , Cucurbita/química , Cucurbita/metabolismo , Fluoruros/metabolismo , Hidrocarburos Clorados/metabolismo , Estructura Molecular , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Brotes de la Planta/química , Brotes de la Planta/metabolismo , Contaminantes del Suelo/metabolismo , Glycine max/química , Glycine max/metabolismo , Ácidos Sulfúricos/metabolismo , Triticum/química , Triticum/metabolismo , Zea mays/química , Zea mays/metabolismo
4.
Biotechnol Appl Biochem ; 67(5): 738-743, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31532860

RESUMEN

Marine biomass, especially the algal biomass, is currently considered to be one of the most potential candidates for biofuels conversion during the development of biomass utilization. In this study, a diluted sulfuric acid pretreatment method was established for biobutanol from red algal biomass Gelidium amansii using a newly isolated Clostridium sp. strain WK. Under the optimal condition of 2% sulfuric acid treated in 20 Min at 131 °C, the maximal hydrolysis percentage of biomass can reach up to 80.95%, and the biobutanol production was obtained to be 3.46 g/L with a yield of 0.20 g/g after the fermentation of biomass hydrolysate. This result demonstrated a 12.5-fold enhancement of conversion efficiency compared with the untreated control, which provides a new and efficient way to develop the biobutanol industry by utilizing the abundant, low cost, and carbohydrate-rich algal biomass.


Asunto(s)
Biocombustibles , Butanoles/metabolismo , Clostridium/metabolismo , Rhodophyta/metabolismo , Ácidos Sulfúricos/metabolismo , Biocombustibles/análisis , Biocombustibles/microbiología , Biomasa , Butanoles/análisis , Fermentación , Hidrólisis
5.
Prep Biochem Biotechnol ; 50(2): 181-190, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31647386

RESUMEN

The synergism of cellulase (C), pectinase (P), and xylanase (X) for the saccharification of sweet potato residues (SPR) was investigated. The removal of starch from SPR was easily achieved by using amylase, but the cellulose conversion of de-starched SPR was relatively low, thus dilute H2SO4, NaOH, and H2O2 pretreatment was conducted to improve the enzymatic digestibility. The lignin content of NaOH pretreated SPR was the lowest, whereas H2SO4 pretreatment resulted in the lowest contents of hemicellulose and pectin. The combination of C, P, and X exhibited different sugar production patterns, C-P displayed synergistic action on glucose and galactose production from each type of SPR, C-X also exhibited synergistic effect on glucose production except when H2SO4 pretreated SPR was used, whereas no synergism between P-X on monosaccharide production was observed. The presence of synergism between cellulase and mixed accessory enzymes [C-(PX)] on glucose formation was determined by C-X, and the degree of synergism between C-P and C-(PX) on glucose production had a positive relationship with pectin content. The highest cellulose conversion of 96.2% was obtained from NaOH pretreated SPR using mixed enzymes comprising C, P, and X with the ratio of 8:1:1.


Asunto(s)
Celulasa/metabolismo , Endo-1,4-beta Xilanasas/metabolismo , Ipomoea batatas/metabolismo , Poligalacturonasa/metabolismo , Hidrólisis , Ipomoea batatas/química , Ácidos Sulfúricos/metabolismo
6.
Sci Rep ; 9(1): 16709, 2019 11 13.
Artículo en Inglés | MEDLINE | ID: mdl-31723189

RESUMEN

In the present work, sustainable nanomaterials, cellulose, and spherical cellulose nanocrystals (SCNCs) were isolated from the non-edible parts of jackfruit (Artocarpus heterophyllus). Of the three different methods tested, sodium chlorite treatment produced the highest yield of cellulose, 20.08 ± 0.05% w/w (dry weight). Peaks observed in CP/MAS 13C NMR spectrum and FTIR frequencies revealed the presence of α-cellulose and absence of other biomass fractions like hemicellulose and lignin. XRD analysis showed a high crystallinity of 83.42%. An appearance of a sharp endothermal peak at 323 °C in DSC and decomposition patterns between 310-420 °C of TGA confirms the presence of cellulose. Further, Sulphuric acid hydrolysis was employed to produce SCNCs and examined by TEM for the morphology and by HPLC for the presence of glucose.


Asunto(s)
Artocarpus/química , Artocarpus/crecimiento & desarrollo , Celulosa/química , Celulosa/aislamiento & purificación , Nanopartículas/química , Ácidos Sulfúricos/metabolismo , Hidrólisis
7.
ACS Synth Biol ; 8(11): 2514-2523, 2019 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-31622552

RESUMEN

Plants possess myriads of secondary metabolites with a broad spectrum of health-promoting benefits. To date, plant extraction is still the primary route to produce high-value natural products which inherently suffers from economics and scalability issues. Heterologous expression of plant biosynthetic gene clusters in microbial host is considered as a feasible approach to overcoming these limitations. Oleaginous yeast produces a large amount of lipid bodies, the abundant membrane structure and the lipophilic environment provide the ideal environment for the regioselectivity and stereoselectivity of many plant-derived P450 enzymes. In this work, we used modular method to construct, characterize, and optimize the flavonoid pathways in Yarrowia lipolytica. We also evaluated various precursor biosynthetic routes and unleashed the metabolic potential of Y. lipolytica to produce flavonoids and hydroxylated flavonoids. Specifically, we have identified that chalcone synthase (CHS) and cytochrome P450 reductases (CPR) were the bottlenecks of hydroxylated flavonoid production. We determined the optimal gene copy number of CHS and CPR to be 5 and 2, respectively. We further removed precursor pathway limitations by expressing genes associated with chorismate and malonyl-CoA supply. With pH and carbon-nitrogen ratio (C/N) optimization, our engineered strain produced 252.4 mg/L naringenin, 134.2 mg/L eriodictyol, and 110.5 mg/L taxifolin from glucose in shake flasks. Flavonoid and its hydroxylated derivatives are most prominently known as antioxidant and antiaging agents. These findings demonstrate our ability to harness the oleaginous yeast as the microbial workhorse to expand nature's biosynthetic potential, enabling us to bridge the gap between drug discovery and natural product manufacturing.


Asunto(s)
Reactores Biológicos , Flavanonas/biosíntesis , Ingeniería Metabólica/métodos , Quercetina/análogos & derivados , Yarrowia/genética , Yarrowia/metabolismo , Aciltransferasas/genética , Ácido Corísmico/genética , Ácido Corísmico/metabolismo , Expresión Génica , Glucosa/metabolismo , Concentración de Iones de Hidrógeno , Hidroxilación , Malonil Coenzima A/genética , Malonil Coenzima A/metabolismo , NADPH-Ferrihemoproteína Reductasa/genética , Quercetina/biosíntesis , Ácidos Sulfúricos/metabolismo , Biología Sintética/métodos
8.
PLoS One ; 14(8): e0220706, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31393920

RESUMEN

Fetida Cave is an active sulfuric acid cave influenced by seawater, showing abundant microbial communities that organize themselves under three main different morphologies: water filaments, vermiculations and moonmilk deposits. These biofilms/deposits have different cave distribution, pH, macro- and microelement and mineralogical composition, carbon and nitrogen content. In particular, water filaments and vermiculations had circumneutral and slightly acidic pH, respectively, both had abundant organic carbon and high microbial diversity. They were rich in macro- and microelements, deriving from mineral dissolution, and, in the case of water filaments, from seawater composition. Vermiculations had different color, partly associated with their mineralogy, and unusual minerals probably due to trapping capacities. Moonmilk was composed of gypsum, poor in organic matter, had an extremely low pH (0-1) and low microbial diversity. Based on 16S rRNA gene analysis, the microbial composition of the biofilms/deposits included autotrophic taxa associated with sulfur and nitrogen cycles and biomineralization processes. In particular, water filaments communities were characterized by bacterial taxa involved in sulfur oxidation and reduction in aquatic, aphotic, microaerophilic/anoxic environments (Campylobacterales, Thiotrichales, Arenicellales, Desulfobacterales, Desulforomonadales) and in chemolithotrophy in marine habitats (Oceanospirillales, Chromatiales). Their biodiversity was linked to the morphology of the water filaments and their collection site. Microbial communities within vermiculations were partly related to their color and showed high abundance of unclassified Betaproteobacteria and sulfur-oxidizing Hydrogenophilales (including Sulfuriferula), and Acidiferrobacterales (including Sulfurifustis), sulfur-reducing Desulfurellales, and ammonia-oxidizing Planctomycetes and Nitrospirae. The microbial community associated with gypsum moonmilk showed the strong dominance (>60%) of the archaeal genus Thermoplasma and lower abundance of chemolithotrophic Acidithiobacillus, metal-oxidizing Metallibacterium, Sulfobacillus, and Acidibacillus. This study describes the geomicrobiology of water filaments, vermiculations and gypsum moonmilk from Fetida Cave, providing insights into the microbial taxa that characterize each morphology and contribute to biogeochemical cycles and speleogenesis of this peculiar seawater-influenced sulfuric acid cave.


Asunto(s)
Cuevas/microbiología , Microbiota , Agua de Mar/química , Ácidos Sulfúricos/metabolismo , Bacterias/aislamiento & purificación , Biodiversidad , Biopelículas , Crecimiento Quimioautotrófico , Oxidación-Reducción , Filogenia , Azufre/metabolismo
9.
Biotechnol Prog ; 35(4): e2830, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31050199

RESUMEN

In this work, we performed recovery of ethanol from a fermentation broth of banana pseudostem by pervaporation (PV) as a lower-energy-cost alternative to traditional separation processes such as distillation. As real fermentation systems generally contain by-products, it was investigated the effects of different components from the fermentation broth of banana pseudostem on PV performance for ethanol recovery through commercial flat sheet polydimethylsiloxane (PDMS) membrane. The experiments were compared to a binary solution (ethanol/water) to determine differences in the results due to the presence of fermentation by-products. A real fermented broth of banana pseudostem was also used as feed for the PV experiments. Seven by-products from fermented broth were identified: propanol, isobutanol, methanol, isoamyl alcohol, 1-pentanol, acetic acid, and succinic acid. Moreover, the residual sugar content of 3.02 g/L1 was obtained. The presence of methanol showed the best results for total permeate flux (0.1626 kg·m-2 ·h-1 ) and ethanol permeate flux (0.0391 kg·m-2 ·h-1 ) during PV at 25°C and 3 wt% ethanol, also demonstrated by the selectivity and enrichment factor. The lowest total fluxes of permeate were observed in the experiments containing the acids. Better permeance of 0.1171 from 0.0796 kg·m-2 ·h-1 and membrane selectivity of 9.77 from 9.30 were obtained with real fermentation broth than with synthetic solutions, possibly due to the presence of by-products in the multicomponent mixtures, which contributed to ethanol permeation. The results of this work indicate that by-products influence pervaporation of ethanol with hydrophobic flat sheet membrane produced from the fermented broth of banana pseudostem.


Asunto(s)
Etanol/aislamiento & purificación , Fermentación , Musa/metabolismo , Dimetilpolisiloxanos/química , Dimetilpolisiloxanos/metabolismo , Etanol/química , Etanol/metabolismo , Hidrólisis , Musa/química , Ácidos Sulfúricos/química , Ácidos Sulfúricos/metabolismo , Volatilización
10.
J Biosci Bioeng ; 128(3): 344-354, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31014562

RESUMEN

Benefiting from lower operational costs and energy requirements than do hydrometallurgical and pyrometallurgical processes in metal recovery, the bioleaching of LiCoO2 through the use of sulfur-oxidizing and iron-oxidizing bacteria has drawn increasing attention. However, the bioleaching mechanism of LiCoO2 has not been clearly elaborated. In the present study, the effects of the energy source of bacteria, such as Fe2+, pyrite and S0, and the products of bacterial oxidation, such as Fe3+ and sulfuric acid, on the chemical leaching of LiCoO2 were studied. The results indicated that lithium was dissolved by acid, and cobalt was released by the reduction of Fe2+ and acid dissolution. The recovery of Li+ and Co2+ could be significantly improved by pH adjustment. Finally, optimal recoveries of Li+ and Co2+ were observed in the pyrite group, reaching 91.4% and 94.2%, respectively. By using pyrite as the energy source, the role of bacteria in bioleaching of LiCoO2 was investigated. The results showed that bacteria could produce sulfuric acid by oxidizing pyrite to promote the mobilization of Li+ and Co2+. The recovery of lithium and cobalt could be increased to 100.0% and 99.3% by bacteria. Moreover, extracellular polymeric substances secreted by bacteria were found to be a factor for the improvement of Li+ and Co2+ recovery.


Asunto(s)
Bacterias/metabolismo , Cobalto/farmacocinética , Hierro/metabolismo , Metalurgia , Óxidos/farmacocinética , Azufre/metabolismo , Acidithiobacillus/metabolismo , Acidithiobacillus thiooxidans/metabolismo , Bacillus/metabolismo , Biodegradación Ambiental , Cobalto/química , Suministros de Energía Eléctrica , Equipo Reutilizado , Concentración de Iones de Hidrógeno , Litio/farmacocinética , Metalurgia/métodos , Oxidación-Reducción , Óxidos/química , Sulfuros/metabolismo , Azufre/química , Ácidos Sulfúricos/metabolismo , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/farmacocinética
11.
J Hazard Mater ; 360: 504-511, 2018 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-30144769

RESUMEN

Applying biohydrometallurgy for metal extraction and recovery from mixed and polymetallic wastes such as electronic waste is limited due to microbial inhibition at low pulp densities and substrate (iron and sulfur) limitation. Here, we investigated the application of indirect non-contact bioleaching with biogenic ferric iron and sulfuric acid to extract metals from lithium-ion battery (LIB) waste. Results showed that although a single leach stage at ambient temperature only facilitated low leach yields (<10%), leach yields for all metals improved with multiple sequential leach stages (4 × 1 h). Biogenic ferric leaching augmented with 100 mM H2SO4 further enabled the highest leach yields (53.2% cobalt, 60.0% lithium, 48.7% nickel, 81.8% manganese, 74.4% copper). The proposed use of bioreagents is a viable and a more environmentally benign alternative to traditional mineral processing, which could be further improved by appropriate pre-treatment of the LIB waste.


Asunto(s)
Suministros de Energía Eléctrica , Residuos Electrónicos , Hierro/química , Litio/química , Ácidos Sulfúricos/química , Acidithiobacillus/metabolismo , Hierro/metabolismo , Reciclaje/métodos , Ácidos Sulfúricos/metabolismo
12.
Bioelectrochemistry ; 123: 34-44, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29723805

RESUMEN

Microbiologically influenced corrosion (MIC) of S32654 (654SMO) super austenitic stainless steel (SASS) by acid producing bacterium (APB), Acidithiobacillus caldus SM-1, a strain of sulfur-oxidizing bacteria (SOB) used in biohydrometallurgy field, was investigated using electrochemical measurements and surface characterizations during a 14-day immersion test. The results indicated that S32654 SASS was susceptible to MIC by APB, and A. caldus SM-1 was capable of producing an aggressive acidic environment underneath the biofilm, resulting in the dissolution of the passive film and severe pitting attacks against S32654 SASS, which is commonly regarded as a corrosion resistant material.


Asunto(s)
Acidithiobacillus/fisiología , Acero Inoxidable/química , Ácidos Sulfúricos/metabolismo , Acidithiobacillus/química , Biopelículas , Corrosión , Técnicas Electroquímicas , Ácidos Sulfúricos/química , Propiedades de Superficie
13.
Chemosphere ; 203: 26-33, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29604427

RESUMEN

Malonic acid (MOA), one of the major dicarboxylic acids (DCAs) in aerosols, has been identified experimentally and computationally to be a strong acid. However, its potential role in the atmospheric clusters formation is still ambiguous. Hence, the participant mechanism of MOA on the formation of atmospheric sulfuric acid (SA)- ammonia (A) clusters was investigated by combining computational methods with atmospheric cluster dynamics code (ACDC). The most stable molecular structures obtained at the M06-2X/6-311++G(3df,3pd) level of theory shows that the added MOA molecule in the SA-A-based clusters presents a promotion on the interactions between SA and A molecules. ACDC simulations indicate directly an obvious enhancement strength RMOA on the clusters formation rates at 218 K and the concentration of MOA ([MOA]) larger than 108 molecules cm-3, up to five orders of magnitude. Meanwhile, enhancement strength of MOA is compared with that of glycolic acid, and as expected, MOA presents a superior enhancement strength. Both RMOA and the compared enhancement strength (rcom) present a positive dependency on [MOA] and a negative dependency on [SA]. With the increase of [A], both RMOA and rcom (except at [SA] = 104 molecules cm-3) first increase, reaching the maximum value and then decrease. Finally, a catalytic participant mechanism of MOA where MOA acts as a mediate bridge for the formation of pure SA-A-based clusters has been identified by tracing the main growth pathways of the system.


Asunto(s)
Aerosoles/química , Amoníaco/química , Malonatos/química , Ácidos Sulfúricos/metabolismo , Catálisis , Estructura Molecular
14.
J Microbiol Biotechnol ; 28(5): 732-738, 2018 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-29551017

RESUMEN

Novel carbon-based solid acid catalysts were synthesized through a sustainable route from lipid-extracted microalgal residue of Dunaliella tertiolecta, for biodiesel production. Two carbon-based solid acid catalysts were prepared by surface modification of bio-char with sulfuric acid (H2SO4) and sulfuryl chloride (SO2Cl2), respectively. The treated catalysts were characterized and their catalytic activities were evaluated by esterification of oleic acid. The esterification catalytic activity of the SO2Cl2-treated bio-char was higher (11.5 mmol Prod.∙h⁻¹âˆ™g Cat. ⁻¹) than that of commercial catalyst silica-supported Nafion SAC-13 (2.3 mmol Prod.∙h⁻¹âˆ™g Cat. ⁻¹) and H2SO4-treated bio-char (5.7 mmol Prod.∙h⁻¹âˆ™g Cat. ⁻¹). Reusability of the catalysts was examined. The catalytic activity of the SO2Cl2-modified catalyst was sustained from the second run after the initial activity dropped after the first run and kept the same activity until the fifth run. It was higher than that of first-used Nafion. These experimental results demonstrate that catalysts from lipid-extracted algae have great potential for the economic and environment-friendly production of biodiesel.


Asunto(s)
Biocombustibles , Microalgas , Volvocida , Biotecnología , Carbono/química , Carbono/metabolismo , Catálisis , Esterificación , Lípidos , Microalgas/química , Microalgas/metabolismo , Ácidos Sulfúricos/química , Ácidos Sulfúricos/metabolismo , Volvocida/química , Volvocida/metabolismo
15.
Prep Biochem Biotechnol ; 48(1): 75-83, 2018 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-29194020

RESUMEN

A novel and effective process was put forward for converting rice straw into feed by combining diluted acid hydrolysis and ammonization with Rhodospirillum rubrum fermentation. After pretreatment with dilute sulfuric or phosphoric acid (1%, w/w) at 100°C, materials were subjected to fermentation under several gases (N2, CO2, and air) and different light intensities in a 2-L fermentor. The key indexes of feed for fermented materials were estimated and several toxic substances were investigated during the fermentation. Following sulfuric acid treatment, the true protein of rice straw increased from 29 to 143 g kg-1 and the crude fiber decreased from 359 to 136 g kg-1 after fermentation at 0.3 L min-1 L-1 of N2 flow and a light intensity of 3400 lux; and following phosphoric acid treatment, the true protein increased by 286% and the crude fiber decreased by 52% after fermentation at 0.4 L min-1 L-1 of N2 flow and a light intensity of 3000 lux. Other key contents were also improved for use as feed, and some toxic substances (i.e., furfural, hydroxymethylfurfural, acetic acid, phenol, cresol) produced by the pretreatments could be removed at low levels during the fermentations.


Asunto(s)
Alimentación Animal/análisis , Oryza/metabolismo , Rhodospirillum rubrum/metabolismo , Alimentación Animal/toxicidad , Fermentación , Hidrólisis , Microbiología Industrial , Luz , Ácidos Fosfóricos/metabolismo , Ácidos Sulfúricos/metabolismo
16.
World J Microbiol Biotechnol ; 33(10): 184, 2017 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-28948457

RESUMEN

This paper reports an effective process for converting soy sauce residue into feeds by combining moderate acid hydrolysis and ammonization with Rhodospirillum rubrum fermentation. After pretreatment with dilute sulfuric or phosphoric acid (1%, w/w) at 100 °C, materials were subjected to fermentation under several gases (N2, CO2, and air) and different light intensities in a 2-L fermentor. Following sulfuric acid treatment, the true protein increased from 188 to 362 g kg-1 and the crude fiber decreased from 226 to 66 g kg-1 after fermentation at 0.5 L min-1 L-1 of air flow and a light intensity of 750 lx and following phosphoric acid treatment, the true protein increased by 90% and the crude fiber decreased by 67% after fermentation at 0.6 L min-1 L-1 of air flow and a light intensity of 600 lx Other contents, including crude fat, crude ash, phosphorus, sulfur, sulfur-containing amino acids, sodium chloride, and calcium, were also improved for use as feed. Meantime, some toxic substances, including furfural, hydroxymethylfurfural (5-HMF), acetic acid, phenol, and cresol, which were produced by the pretreatments, could be removed by 12-32, 5-8, 49-53, 7-8, and 7-8%, respectively; and total sugars, glucose, and xylose could be utilized by 68-69, 71-72, and 63-67% respectively. The quality of soy sauce residue is improved for use as feed and some toxic substances can be decreased via the R. rubrum fermentation.


Asunto(s)
Inactivación Metabólica , Rhodospirillum rubrum/crecimiento & desarrollo , Alimentos de Soja/microbiología , Alimentación Animal/análisis , Alimentación Animal/microbiología , Alimentación Animal/toxicidad , Fermentación , Microbiología Industrial , Alimentos de Soja/análisis , Alimentos de Soja/toxicidad , Ácidos Sulfúricos/metabolismo
17.
Sci Rep ; 7(1): 6000, 2017 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-28729681

RESUMEN

The giant triton snail (Charonia tritonis) is one of the few natural predators of the adult Crown-of-Thorns starfish (COTS), a corallivore that has been damaging to many reefs in the Indo-Pacific. Charonia species have large salivary glands (SGs) that are suspected to produce either a venom and/or sulphuric acid which can immobilize their prey and neutralize the intrinsic toxic properties of COTS. To date, there is little information on the types of toxins produced by tritons. In this paper, the predatory behaviour of the C. tritonis is described. Then, the C. tritonis SG, which itself is made up of an anterior lobe (AL) and posterior lobe (PL), was analyzed using an integrated transcriptomics and proteomics approach, to identify putative toxin- and feeding-related proteins. A de novo transcriptome database and in silico protein analysis predicts that ~3800 proteins have features consistent with being secreted. A gland-specific proteomics analysis confirmed the presence of numerous SG-AL and SG-PL proteins, including those with similarity to cysteine-rich venom proteins. Sulfuric acid biosynthesis enzymes were identified, specific to the SG-PL. Our analysis of the C. tritonis SG (AL and PL) has provided a deeper insight into the biomolecular toolkit used for predation and feeding by C. tritonis.


Asunto(s)
Genómica/métodos , Conducta Predatoria , Glándulas Salivales/metabolismo , Caracoles/genética , Estrellas de Mar/fisiología , Secuencia de Aminoácidos , Animales , Proteínas/química , Proteínas/genética , Proteómica , Glándulas Salivales/anatomía & histología , Ácidos Sulfúricos/metabolismo , Transcriptoma
18.
Bioresour Technol ; 230: 90-96, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28161625

RESUMEN

A novel pretreatment process was developed to achieve valorization of bamboo components into digestible cellulose, degraded sugars and lignin. In this case, bamboo was pretreated with 60% γ-valerolactone (GVL)/40% water containing 0.05mol/L H2SO4, yielding solid fraction rich in cellulose. The resulting liquor was further treated with the addition of NaCl and ultrasound, resulting in water phase rich in degraded sugars and GVL phase containing lignin, which was easy to recover. Results showed that the enzymatic hydrolysis was enhanced by 6.7-fold after treatment as compared to the control. The degraded sugars released in water phase contained monosaccharides (70.72-160.47g/kg) together with oligo- and polysaccharides (46.4-181.85g/kg). The lignin obtained had high purity, low molecular weight (1820-2970gmol-1) and low polydispersity (1.93-1.98). The present study creates a novel pretreatment process for the conversion of Gramineae biomass into useful feedstocks with potential applications in the fields of fuels, chemicals and polymers.


Asunto(s)
Celulosa/biosíntesis , Lactonas/metabolismo , Lignina/biosíntesis , Poaceae/metabolismo , Ácidos Sulfúricos/metabolismo , Agua/metabolismo , Biomasa , Metabolismo de los Hidratos de Carbono , Fraccionamiento Químico , Glucosa/metabolismo , Hidrólisis
19.
BMC Microbiol ; 16(1): 153, 2016 07 18.
Artículo en Inglés | MEDLINE | ID: mdl-27430211

RESUMEN

BACKGROUND: Biogenic sulfuric acid (BSA) corrosion damages sewerage and wastewater treatment facilities but is not well investigated in sludge digesters. Sulfur/sulfide oxidizing bacteria (SOB) oxidize sulfur compounds to sulfuric acid, inducing BSA corrosion. To obtain more information on BSA corrosion in sludge digesters, microbial communities from six different, BSA-damaged, digesters were analyzed using culture dependent methods and subsequent polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). BSA production was determined in laboratory scale systems with mixed and pure cultures, and in-situ with concrete specimens from the digester headspace and sludge zones. RESULTS: The SOB Acidithiobacillus thiooxidans, Thiomonas intermedia, and Thiomonas perometabolis were cultivated and compared to PCR-DGGE results, revealing the presence of additional acidophilic and neutrophilic SOB. Sulfate concentrations of 10-87 mmol/L after 6-21 days of incubation (final pH 1.0-2.0) in mixed cultures, and up to 433 mmol/L after 42 days (final pH <1.0) in pure A. thiooxidans cultures showed huge sulfuric acid production potentials. Additionally, elevated sulfate concentrations in the corroded concrete of the digester headspace in contrast to the concrete of the sludge zone indicated biological sulfur/sulfide oxidation. CONCLUSIONS: The presence of SOB and confirmation of their sulfuric acid production under laboratory conditions reveal that these organisms might contribute to BSA corrosion within sludge digesters. Elevated sulfate concentrations on the corroded concrete wall in the digester headspace (compared to the sludge zone) further indicate biological sulfur/sulfide oxidation in-situ. For the first time, SOB presence and activity is directly relatable to BSA corrosion in sludge digesters.


Asunto(s)
Acidithiobacillus thiooxidans/metabolismo , Betaproteobacteria/metabolismo , Aguas del Alcantarillado/microbiología , Azufre/metabolismo , Ácidos Sulfúricos/metabolismo , Acidithiobacillus thiooxidans/genética , Acidithiobacillus thiooxidans/aislamiento & purificación , Betaproteobacteria/genética , Betaproteobacteria/aislamiento & purificación , Biopelículas , Corrosión , Medios de Cultivo , Electroforesis en Gel de Gradiente Desnaturalizante/métodos , Oxidación-Reducción , Filogenia , Reacción en Cadena de la Polimerasa/métodos , ARN Ribosómico 16S/genética , Compuestos de Azufre/metabolismo
20.
Anal Chim Acta ; 929: 39-48, 2016 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-27251947

RESUMEN

The present study deals with the photophysical property of a pyrene-benzthiazolium conjugate R1, as a strong intramolecular charge transfer (ICT) probe exhibiting long wavelength emission in the red region. Unlike traditional planar polyaromatic hydrocarbons whose aggregation generally quenches the light emission, the pyrene based R1 was found to display aggregation-induced emission (AIE) property along with simultaneous increase in its quantum yield upon increasing the water content of the medium. The R1 exhibits high specificity towards HSO3(-)/SO3(2-) by interrupting its own ICT producing there upon a large ratiometric blue shift of ∼220 nm in its emission spectrum. The lowest detection limit for the above measurement was found to be 8.90 × 10(-8) M. The fluorescent detection of HSO3(-) was also demonstrated excellently by test paper strip and silica coated TLC plate incorporating R1. The live cell imaging of HSO3(─) through R1 in HeLa cells was studied using fluorescence microscopic studies. The particle size and morphological features of R1 and R1-HSO3(-) aggregates in aqueous solution were characterized by DLS along with SEM analysis.


Asunto(s)
Imagen Molecular/métodos , Pirenos/química , Ácidos Sulfúricos/metabolismo , Tiazoles/química , Supervivencia Celular , Células HeLa , Humanos , Modelos Moleculares , Conformación Molecular , Espectrometría de Fluorescencia , Ácidos Sulfúricos/química
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