RESUMEN
Molasses wastewater contains high levels of organic compounds, cations, and anions, causing operational problems for anaerobic biological treatment. In this study, an upflow anaerobic filter (UAF) reactor was employed to establish a high organic loading treatment system for molasses wastewater and further investigated the microbial community dynamics in response to this stressful operation. The biogas production increased with an increase in total organic carbon (TOC) loading rate from 1.0 to 14 g/L/day, and then it decreased with further TOC loading rate addition until 16 g/L/day. The UAF reactor achieved a maximum biogas production of 6800 mL/L/day with a TOC removal efficiency of 66.5% at a TOC loading rate of 14 g/L/day. Further microbial analyses revealed that both the bacterial and archaeal communities developed multiple strategies to maintain stable operation of the reactor at high organic loading (e.g., Proteiniphilum and Defluviitoga maintained high abundances throughout the operation; Tissierella temporarily dominated the bacterial community at TOC loading rates of 8.0 to 14 g/L/day; and multi-trophic Methanosarcina shifted as the dominant methanogen at the TOC loading rates of 8.0 to 16 g/L/day). This study presents insights into a high organic loading molasses wastewater treatment system and the microbial flexibility in methane fermentation in response to process disturbances.
Asunto(s)
Melaza , Aguas Residuales , Anaerobiosis , Melaza/microbiología , Biocombustibles , Reactores Biológicos/microbiología , Metano , Eliminación de Residuos Líquidos , Aguas del Alcantarillado/microbiologíaRESUMEN
Enterococcus sp. has been used as starters in food fermentation due to their probiotic and antimicrobial properties in food biopreservation. The antimicrobial properties were mainly contributed by the bacteriocin called enterocin. Hence, the availability of a cost-effective pilot-scale cultivation conditions is a necessity for the production of probiotic bacteria. This study aims to investigate optimization of medium composition using sugarcane molasses as a carbon source using response surface methodology and the potential use of fed-batch cultivation for improvement of the cell viability of Enterococcus faecium CW3801 for the use as a probiotic starter culture. Two feeding strategies (ramp and constant) were applied in fed-batch cultivation for enhancement of the production of E. faecium in a 2-L stirred tank bioreactor using the optimized medium and scaled up to a 15-L bioreactor. Optimized fermentation medium which comprised of 10% (v/v) of molasses and 10 g/L of yeast extract at pH 7 yielded maximum cell viability of 29.4 × 1011 CFU/mL with 3900 AU/mL of bacteriocin-like inhibitory substances (BLIS) activity. In the fed-batch, the cell viability (8.4 × 1013) and dry cell weight (6.34 g/L) reached the highest in optimized medium when the ramp (stepwise) feeding was applied. In scaling up to 15-L bioreactor, the growth of E. faecium was achieved at 2.3 × 1013 CFU/mL with the dry cell weight of 5.28 g/L under the same condition. The BLIS in 15-L bioreactor was 6% higher than the 2-L bioreactor. This study demonstrated that molasses and yeast extract are good feedstock for the growth of E. faecium. The E. faecium, a non-vancomycin resistant enterococcus (VRE) was successfully produced by a fed-batch cultivation approach and scaled up to a 15-L bioreactor using a ramp feeding strategy. Results from this study revealed that the fed-batch cultivation using molasses-based medium has industrial potential for the production of probiotics.
Asunto(s)
Bacteriocinas , Enterococcus faecium , Bacteriocinas/farmacología , Reactores Biológicos/microbiología , Medios de Cultivo/química , Fermentación , Melaza/microbiologíaRESUMEN
OBJECTIVE: Tobacco smoking remains a worldwide health issue, and the use of flavored varieties (maassel) embedded in glycerine, molasses, and fruit essence via shisha paraphernalia (waterpipe) is growing globally. 16S rRNA gene pyrosequencing was conducted on 18 different varieties representing 16 flavors and three brands in order to study the microbiota of maassel and find whether it contains pathogenic bacteria. MATERIALS AND METHODS: The samples were selected randomly from the most utilized brands within Albaha, Saudi Arabia as determined through a questionnaire of 253 smokers. In addition, ten-fold serially diluted samples were inoculated on blood agar, MacConkey agar, half-strength trypticase soy agar and malt agar for the enumeration of mesophilic microorganisms, coliforms, Bacillus, thermophilic bacteria, and fungi. RESULTS: A core microbiota was recognized consisting of three phyla (Firmicutes, Proteobacteria and Actinobacteria) and a total of 571 different species were identified including many pathogens, such as Mycobacterium riyadhense, M. chelonae, Shigella sonnei, S. flesneri, Klebsiella pneumoniae, Salmonella bongori, Coxiella burnetii, Acinetobacter spp., Staphylococcus haemolyticus, Streptococcus pseudopneumoniae, and Streptococcus sanguinis, showing the contamination of maassel. CONCLUSIONS: The present study suggests that flavored tobaccos are potentially infectious. However, further risk assessment is required to determine transmission occurrence.
Asunto(s)
Melaza/microbiología , Humanos , Arabia SauditaRESUMEN
BACKGROUND AND OBJECTIVE: Barley straw is a farm by product that may be useful in animal feeding but its use is limited due to its low nutritional value and high fiber content. Therefore, this study aimed to improving the nutritive value of barley straw by bacterial treatment with Condensed Molasses Soluble (CMS) in the ration of Barki lambs. MATERIALS AND METHODS: In Experiment 1, 12 Barki rams, which were divided into 3 equal groups (4 each), were given rations which consisted of 50% CFM+50%, either clover hay (C) or bacterial treated barley straw (T1) or T1+ CMS (T2). In Experiment 2, 10 Barki lambs were divided into 2 groups, one (C) and T2 as descripted in Experiment 1. Data analyzed by using one way ANOVA model. RESULTS: Digestibility of Dry Matter (DM), Organic Matter (OM), Crude Fiber (CF) and Ether Extract (EE) were insignificantly affected among all rations, while Digestible Crude Protein (DCP) recorded a higher value in T2 compared to T1. Changes in Total Digestible Nutrients (TDN) values were insignificant. Values of DCP were higher for T2 compared to C and T1. The Body Weight Gain (BWG) and Feed Conversion Ratio (FCR) of growing lambs didn't statistically differ among the groups. CONCLUSION: Finally, complete replacement of clover hay by treated barley straw plus CMS may be considered good feeding strategies in the feeding of Barki lambs in Arid and semi-arid regions.
Asunto(s)
Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Producción de Cultivos , Productos Agrícolas/crecimiento & desarrollo , Hordeum/crecimiento & desarrollo , Medicago/crecimiento & desarrollo , Ovinos/crecimiento & desarrollo , Animales , Clima , Productos Agrícolas/microbiología , Suplementos Dietéticos/microbiología , Fermentación , Hordeum/microbiología , Melaza/microbiología , Estado Nutricional , Valor Nutritivo , Factores de Tiempo , Aumento de PesoRESUMEN
Three culture media were studied for red pigment production by Monascus ruber in submerged cultivation: rice flour (20 g L-1), sugarcane molasses (30 g L-1), and, finally, molasses + rice flour (10 g L-1+10 g L-1); all culture media were added of 5 g L-1 glycine as nitrogen source. Rice flour showed pigment production of 7.05 UA510nm and molasses 5.08 UA510nm, and the mixture of rice flour and molasses showed the best result of 16.38 UA510nm. Molasses culture presented good results for cell biomass production of 11.09 g L-1. With these results, it was observed that one substrate presented good pigment production (rice flour) and another attained better results for cell biomass growth (molasses), and a third medium containing 10 g L-1 of rice flour + 10 g L-1 of molasses was formulated. The results for this mixture showed satisfactory results, with global pigment productivity of 0.097 UA510nm h-1 and maximum productivity rate of 0.17 UA510nm h-1. The high production and productivity obtained for the mixture of rice flour and molasses indicated that the production of red pigment by submerged fermentation, using the mixture of these low-cost culture media, may be promising in terms of commercial production.
Asunto(s)
Harina/microbiología , Melaza/microbiología , Monascus/metabolismo , Oryza/microbiología , Pigmentos Biológicos/biosíntesis , Saccharum/microbiología , Biotransformación , Fermentación , Harina/análisis , Melaza/análisis , Monascus/crecimiento & desarrollo , Oryza/metabolismo , Saccharum/química , Residuos/análisisRESUMEN
BACKGROUND: The objective was to determine how molasses and Lactobacillus plantarum affect chemical composition, fermentation quality, aerobic stability, and the microbial community of an ensiled mixture of amaranth (Amaranthus hypochondriaus, AF) and rice straw. Treatments were control (C, no addition), L. plantarum (L; 2 × 105 cfu g-1 fresh weight), molasses (M; 40 g kg-1 fresh matter), and their combination (LM). All treatments were ensiled for 1, 3, 5, 7, and 30 days. RESULTS: All additives improved fermentation quality with greater lactic acid (LA), acetic acid, and lower pH than C silage over the ensiling period. The LM silage combination optimized fermentability, manifested as greater LA contents and a more rapid pH reduction during the first 7 days of ensiling than L or M silages. After 30 days of ensiling, inoculant L. plantarum increased Lactobacillus abundance and reduced bacterial diversity and Enterobacteriaceae abundance compared with silage treated with molasses. Molasses addition reduced the relative concentration of structural carbohydrates (neutral and acid detergent fiber, and hemicellulose) after 30 days of ensiling. Finally, there was spoilage after 2 days and 4 days of aerobic exposure in C and LM silages respectively, whereas L silage had not spoiled after 4 days. CONCLUSIONS: Although the combination of L. plantarum and molasses further optimized fermentation characteristics, L silage had better aerobic stability. © 2021 Society of Chemical Industry.
Asunto(s)
Amaranthus/microbiología , Bacterias/aislamiento & purificación , Lactobacillus plantarum/metabolismo , Microbiota , Oryza/microbiología , Ensilaje/microbiología , Aerobiosis , Amaranthus/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/metabolismo , Fermentación , Melaza/análisis , Melaza/microbiología , Oryza/metabolismo , Tallos de la Planta/metabolismo , Tallos de la Planta/microbiología , Ensilaje/análisisRESUMEN
BACKGROUND: The study aimed to evaluate the effect of Lactobacillus casei TH14, cellulase, and molasses combination fermented sugarcane bagasse (SB) as an exclusive roughage source in the total mixed ration (TMR) for mid-lactation 75% crossbred Holstein cows on feed intake, digestibility, ruminal ecology, milk yield and milk composition. Four multiparous mid-lactation crossbred (75% Holstein Friesian and 25% Thai native breed) dairy cows of 439 ± 16 kg body weight, 215 ± 5 days in milk and average milk yield 10 ± 2 kg d-1 were assigned to a 4 × 4 Latin square design. The unfermented SB (SB-TMR), SB fermented with cellulase and molasses (CM-TMR), SB fermented with L. casei TH14 and molasses (LM-TMR), and SB fermented with L. casei TH14, cellulase and molasses (LCM-TMR) were used as dietary treatments. RESULTS: CM-TMR, LM-TMR and LCM-TMR significantly (P < 0.01) increased dry matter and fiber digestibility, gross energy and metabolizable energy intake (P < 0.05), blood glucose, total volatile fatty acids (P < 0.05), propionic acid and milk yield, but decreased ammonia, acetic acid, acetic:propionic ratio and methane production (P < 0.05) when compared with the SB-TMR. Compared with fermented SB treatments, LCM-TMR had lower (P < 0.05) ruminal ammonia and greater blood glucose (P < 0.01); LCM-TMR showed (P < 0.05) greater volatile fatty acids, propionic acid, milk yield and total solids, and lower acetic:propionic ratio (P < 0.01); methane, protozoa and somatic cell count were found to be lowest in LCM-TMR. CONCLUSION: Combination of L. casei TH14 and additives (LCM-TMR) effectively enhanced feed use, rumen ecology and milk production of Holstein Friesian cows. © 2021 Society of Chemical Industry.
Asunto(s)
Alimentación Animal/análisis , Bovinos/metabolismo , Celulasa/metabolismo , Celulosa/metabolismo , Lacticaseibacillus casei/metabolismo , Leche/metabolismo , Melaza/microbiología , Saccharum/microbiología , Animales , Bovinos/crecimiento & desarrollo , Celulasa/química , Celulosa/análisis , Femenino , Fermentación , Lactancia , Melaza/análisis , Rumen/metabolismo , Residuos/análisisRESUMEN
The objectives of this study were to purify Aspergillus niger inulinase produced from sugar-beet molasses in the shaking incubator (100 mL) and stirred-tank bioreactors (5-L and 30-L) by using some downstream processes and to determine enzyme kinetics and characterization. The results showed that the best centrifuge-time combination was 16,873 ×g-5 min with the purification coefficient of 1.4. Besides, with the ultrafiltration process, the inulinase activities yielded using the shaking incubator, pH-controlled/uncontrolled small-scale bioreactors, and large-scale bioreactor were increased from 1101.3, 2079.2, 1561.3, and 787.5 U/mL to 12,065.2, 21,789.0, 11,296.9, and 2948.1 U/mL with purification coefficients of 5.33, 1.38, 1.46, and 1.67, respectively. Additionally, for the inulinase from shaking incubator and pH-uncontrolled bioreactor, the values of Km for inulin and sucrose were 17.8 and 49.4 mg/mL and 28.8 and 25.9 mg/mL, respectively. As the enzyme amount added to the substrate increased, the activity also increased. Mn2+ is the activator of the enzyme, and Cu2+ and Ag+ are inhibitors of the enzyme. The molecular weight of inulinase has been determined to be between 60 and 70 kDa. Consequently, this study ensures valuable and significant information about the purification and characterization of inulinase for industrial implementations.
Asunto(s)
Aspergillus niger/genética , Reactores Biológicos , Fermentación , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/aislamiento & purificación , Melaza/microbiología , Aspergillus niger/enzimología , Centrifugación , Fraccionamiento Químico , Medios de Cultivo , Activación Enzimática , Cinética , Metales/química , Peso Molecular , Especificidad por Sustrato , UltrafiltraciónRESUMEN
To decrease d-lactic acid production cost, sugarcane molasses and soybean meal, low-cost agro-industrial wastes, were selected as feedstock. First, sugarcane molasses was used directly by Lactobacillus delbrueckii S-NL31, and the nutrients were released from soybean meal by protease hydrolysis. Subsequently, to ensure intensive substrate utilization and enhanced d-lactic acid production from sugarcane molasses and soybean meal, adaptation of L. delbrueckii S-NL31 to substrates was performed through adaptive laboratory evolution. After two-phase adaptive laboratory evolution, the evolved strain L. delbrueckii S-NL31-CM3-SBM with improved cell growth and d-lactic acid production on sugarcane molasses and soybean meal was obtained. To decipher the potential reasons for improved fermentation performance, a metabolomics-based approach was developed to profile the differences of intracellular metabolism between initial and evolved strain. The in-depth analysis elucidated how the key factors exerted influence on d-lactic acid biosynthesis. The results revealed that the enhancement of glycolysis pathway and cofactor supply was directly associated with increased lactic acid production, and the reinforcement of pentose phosphate pathway, amino acid metabolism, and oleic acid uptake improved cell survival and growth. These might be the main reasons for significantly improved d-lactic acid production by adaptive laboratory evolution. Finally, fed-batch simultaneous enzymatic hydrolysis of soybean meal and fermentation process by evolved strain resulted in d-lactic acid levels of 112.3 g/L, with an average production efficiency of 2.4 g/(L × h), a yield of 0.98 g/g sugar, and optical purity of 99.6%. The results show the applicability of d-lactic acid production in L. delbrueckii fed on agro-industrial wastes through adaptive laboratory evolution.
Asunto(s)
Glycine max/microbiología , Ácido Láctico/biosíntesis , Lactobacillus delbrueckii/metabolismo , Saccharum/microbiología , Fermentación , Residuos Industriales/análisis , Lactobacillus delbrueckii/genética , Lactobacillus delbrueckii/crecimiento & desarrollo , Metabolómica , Melaza/análisis , Melaza/microbiología , Saccharum/metabolismo , Glycine max/metabolismo , Residuos/análisisRESUMEN
Modelling has recently become a key tool to promote the bioethanol industry and to optimise the fermentation process to be easily integrated into the industrial sector. In this context, this study aims at investigating the applicability of two mathematical models (Andrews and Monod) for molasses fermentation. The kinetics parameters for Monod and Andrews were estimated from experimental data using Matlab and OriginLab software. The models were simulated and compared with another set of experimental data that was not used for parameters' estimation. The results of modelling showed that µmax = 0.179 1/h and Ks = 11.37 g.L-1 for the Monod model, whereas µmax = 0.508 1/h, Ks = 47.53 g.L-1 and Ki = 181.01 g.L-1 for the Andrews model, which are too close to the values reported in previous studies. The validation of both models showed that the Monod model is more suitable for batch fermentation modelling at a low concentration, where the highest R squared was observed at S0 = 75 g.L-1 with an R squared equal to 0.99956, 0.99954, and 0.99859 for the biomass, substrate, and product concentrations, respectively. In contrast, the Andrews model was more accurate at a high initial substrate concentration and the model data showed a good agreement compared to the experimental data of batch fermentation at S0 = 225 g.L-1, which was reflected in a high R squared with values 0.99795, 0.99903, and 0.99962 for the biomass, substrate, and product concentrations respectively.
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Etanol/metabolismo , Melaza/microbiología , Técnicas de Cultivo Celular por Lotes , Fermentación , Modelos BiológicosRESUMEN
Consecutive dark-fermentation and photo-fermentation stages were investigated for a profitable circular bio-economy. H2 photo-production versus poly(3-hydroxybutyrate) (P3HB) accumulation is a modern biotechnological approach to use agro-food industrial byproducts as no-cost rich-nutrient medium in eco-sustainable biological processes. Whey and molasses are very important byproducts rich in nutrients that lactic acid bacteria can convert, by dark-fermentation, in dark fermented effluents of whey (DFEW) and molasses (DFEM). These effluents are proper media for culturing purple non-sulfur bacteria, which are profitable producers of P3HB and H2. The results of the present study show that Lactobacillus sp. and Rhodopseudomonas sp. S16-VOGS3 are two representative genera for mitigation of environmental impact. The highest productivity of P3HB (4.445â¯mg/(L·h)) was achieved culturing Rhodopseudomonas sp. S16-VOGS3, when feeding the bacterium with 20% of DFEM; the highest H2 production rate of 4.46â¯mL/(L·h) was achieved when feeding the bacterium with 30% of DFEM.
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Lactobacillus/crecimiento & desarrollo , Melaza/microbiología , Rhodopseudomonas/crecimiento & desarrollo , Suero Lácteo/microbiología , Técnicas de Cultivo Celular por Lotes , Fermentación , Hidrógeno/metabolismo , Hidroxibutiratos/análisis , Lactobacillus/metabolismo , Fotobiorreactores/microbiología , Poliésteres/análisis , Rhodopseudomonas/metabolismoRESUMEN
BACKGROUND: Growing challenges of resource depletion, food security and environmental protection are putting stress on the development of biorefinery processes for bioprocessing of residues from food and agro-industry into value-added products. In this study, the simultaneous production of lactic acid (LA) and livestock feed on a combined substrate based on molasses and potato stillage by Lactobacillus paracasei NRRL B-4564 immobilized onto sunflower seed hull (SSH), brewer's spent grain (BSG) and sugar beet pulp (SBP) was studied. RESULTS: The highest total LA concentration of 399 g L-1 with overall productivity of 1.27 g L-1 h-1 was achieved in repeated batch fermentation by SBP-immobilized biocatalyst, followed by BSG- and SSH-immobilized cells. Fermentation improved the content of proteins and ash, and decreased the content of fibers in all three support materials. In addition, the fermentation had favorable effect on in vitro dry matter digestibility and energy values of SSH and BSG. According to assessment of probiotic potential, L. paracasei demonstrated a favorable probiotic profile, exhibiting high resistance to simulated ruminant digestive tract and significant antioxidant and antimicrobial activity. CONCLUSIONS: The proposed strategy enables valorization of agro-industrial residues as value-added ruminant feed and simultaneous LA production. Following principles of circular economy, the developed process combines different raw materials and integrates them into a biorefinery process, improving the overall profitability and productivity. © 2019 Society of Chemical Industry.
Asunto(s)
Alimentación Animal/análisis , Residuos Industriales/análisis , Ácido Láctico/metabolismo , Lacticaseibacillus paracasei/metabolismo , Probióticos/análisis , Agricultura , Alimentación Animal/microbiología , Animales , Fermentación , Lacticaseibacillus paracasei/crecimiento & desarrollo , Melaza/análisis , Melaza/microbiología , Rumen/metabolismo , Rumiantes , Solanum tuberosum/metabolismo , Solanum tuberosum/microbiologíaRESUMEN
A continuous hydrogen and methane production system in a two-stage process has been investigated to increase energy recovery rate from molasses wastewater in this study. This system consisted of a continuous stirred-tank reactor for hydrogen production and an internal circulation (IC) reactor for methane production, and was studied under the influent organic loading rate (OLR) of 18, 24, 30 and 36kg COD/(m3·d) (COD: chemical oxygen demand). The maximum volumetric hydrogen production rate of 2.41 L/(L·d) was obtained at the OLR of 30kg COD/(m3·d) with a hydrogen content of 42%, and the maximum volumetric methane production rate of 2.4 L/(L·d) with a methane content of 74.45% was obtained at the OLR of 36kg COD/(m3·d) using the effluents of hydrogen fermentation as substrate. The maximum of 71.06% of the molasses wastewater energy was converted to biogas (hydrogen and methane) at the OLR of 30kg COD/(m3·d).
Asunto(s)
Metano/biosíntesis , Melaza/microbiología , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química , Anaerobiosis , Reactores Biológicos , HidrógenoRESUMEN
A thermotolerant ethanol fermenting yeast strain is a key requirement for effective ethanol production at high temperature. This work aimed to select a thermotolerant yeast producing a high ethanol concentration from molasses and increasing its ethanol production by mutagenesis. Saccharomyces cerevisiae DMKU 3-S087 was selected from 168 ethanol producing strains because it produced the highest ethanol concentration from molasses at 40 °C. Optimization of molasses broth composition was performed by the response surface method using Box-Behnken design. In molasses broth containing optimal total fermentable sugars (TFS) of 200 g/L and optimal (NH4)2SO4 of 1 g/L, with an initial pH of 5.5 by shaking flask cultivation at 40 °C ethanol, productivity and yield were 58.4 ± 0.24 g/L, 1.39 g/L/h and 0.29 g/g, respectively. Batch fermentation in a 5 L stirred-tank fermenter with 3 L optimized molasses broth adjusted to an initial pH of 5.5 and fermentation controlled at 40 °C and 300 rpm agitation resulted in 72.4 g/L ethanol, 1.21 g/L/h productivity and 0.36 g/g yield at 60 h. Strain DMKU 3-S087 improvement was performed by mutagenesis using ultraviolet radiation and ethyl methane sulfonate (EMS). Six EMS mutants produced higher ethanol (65.2 ± 0.48-73.0 ± 0.54 g/L) in molasses broth containing 200 g/L TFS and 1 g/L (NH4)2SO4 by shake flask fermentation at 37 °C than the wild type (59.8 ± 0.25 g/L). Among these mutants, only mutant S087E100-265 produced higher ethanol (62.5 ± 0.26 g/L) than the wild type (59.5 ± 0.02 g/L) at 40 °C. In addition, mutant S087E100-265 showed better tolerance to high sugar concentration, furfural, hydroxymethylfurfural and acetic acid than the wild type.
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Etanol/metabolismo , Melaza/microbiología , Saccharomyces cerevisiae/metabolismo , Medios de Cultivo/química , Medios de Cultivo/metabolismo , Calor , Microbiología Industrial , Melaza/análisis , Mutagénesis , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Rayos UltravioletaRESUMEN
Twenty-six different bacterial strains were isolated from samples taken from different locations Dammam, Saudi Arabia, for screening of their polyhydroxyalkanoate (PHA) production capability. The initial screening was conducted by staining with Sudan Black B and Nile Red, followed by examination under fluorescence and electron microscopes to characterize PHA granule formation. The PHA-producing bacterial isolates were identified using 16S rRNA gene analyses; the most potent bacterial strain was identified as Pseudomonas sp. strain-P(16). The PHA production capability of this strain in the presence of different low-cost carbon sources, such as rice bran, dates, and soy molasses, was analyzed. PHA production in the presence of rice bran, dates, and soy molasses was 90.9%, 82.6%, and 91.6%, respectively.
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Biopolímeros/biosíntesis , Polihidroxialcanoatos/biosíntesis , Pseudomonas/metabolismo , Biopolímeros/economía , Microbiología Industrial/economía , Microbiología Industrial/métodos , Melaza/análisis , Melaza/microbiología , Polihidroxialcanoatos/economía , Pseudomonas/genética , Pseudomonas/aislamiento & purificación , Residuos/análisis , Residuos/economíaRESUMEN
Hydrogen-producing acetogens (HPA) have a transitional role in anaerobic wastewater treatment. Thus, bioaugmentation with HPA cultures can enhance the chemical oxygen demand (COD) removal efficiency and CH4 yield of anaerobic wastewater treatment. Cultures with high degradation capacities for propionic acid and butyric acid were obtained through continuous subculture in enrichment medium and were designated as Z08 and Z12. Bioaugmentation with Z08 and Z12 increased CH4 production by glucose removal to 1.58. Bioaugmentation with Z08 and Z12 increased the COD removal rate in molasses wastewater from 71.60% to 85.84%. The specific H2 and CH4 yields from COD removal increased by factors of 1.54 and 1.63, respectively. Results show that bioaugmentation with HPA-dominated cultures can improve CH4 production from COD removal. Furthermore, hydrogen-producing acetogenesis was identified as the rate-limiting step in anaerobic wastewater treatment.
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Hidrógeno/metabolismo , Metano/metabolismo , Melaza/microbiología , Aguas Residuales/microbiología , Purificación del Agua/métodos , Anaerobiosis , Análisis de la Demanda Biológica de Oxígeno , Ácido Butírico/metabolismo , Propionatos/metabolismoRESUMEN
OBJECTIVES: This study was conducted to isolate, screening and purification of cellulase from bacteria present in sugar industry waste (molasses) and characterization by morphological and biochemical analysis. RESULTS: Based on experiments, three bacterial strains produced clear transparent zone into carboxymethyl cellulose (CMC) agar plate were identified as cellulase producing bacteria. Different culture parameters such as pH, temperature, incubation period, substrate concentration and carbon sources were optimized for enzyme production. According to the morphological and biochemical tests, the isolated strains were identified as Paenibacillus sp., Bacillus sp. and Aeromonas sp. The first strain Paenibacillus sp. showed high potentiality for maximum cellulase production (0.9 µmol ml-1 min-1) at pH 7.0 after 24 h of incubation at 40 °C in a medium containing 1.0% CMC. Then Paenibacillus sp. was selected for enzyme purification by ammonium sulfate precipitation, DEAE-cellulose and CM-cellulose column chromatography, respectively. In last step of purification, specific activity, recovery and purification fold were 2655 U/mg, 35.7% and 9.7, respectively. The molecular weight of the purified cellulase was found to be 67 kDa by SDS-PAGE, had an optimal pH and temperature at 7.0 and 40 °C. According to substrate specificity, the purified cellulase had high specificity on CMC substrate which indicated it to be an endo-ß-1,4-glucanase.
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Celulasa/aislamiento & purificación , Melaza/microbiología , Aeromonas/enzimología , Bacillus/enzimología , Celulasa/metabolismo , Celulosa , Estabilidad de Enzimas , Concentración de Iones de Hidrógeno , Paenibacillus/enzimología , Especificidad por Sustrato , TemperaturaRESUMEN
AIMS: The goal of this research is to model the effects of two osmotic solutions factors on the reduction of selected microorganisms, and to assess the application in osmotic dehydration process of animal raw materials from the aspect of microbiological safety. METHODS AND RESULTS: Sugar beet molasses and aquatic osmotic solution were prepared and inoculated with Escherichia coli, Listeria monocytogenes and Salmonella spp. Varied factors of osmotic solutions were: time, temperature and concentration of osmotic solutions. Samples of osmotic solutions were subjected to standard and modified microbiological ISO methods. The result showed that increase in factors had a positive effect on the reduction of microbiological load, while the time of the process was the most influential technological parameter. Number of L. monocytogenes was reduced to <10 CFU per g at the end of the process in the highest concentration of sugar beet molasses at all process temperatures. CONCLUSIONS: Developed mathematical models of reduction ratios for tested microorganisms were statistically significant, allowing good prediction of reduction ratio values based on applied factors. SIGNIFICANCE AND IMPACT OF THE STUDY: Obtained levels of reduction of all tested microorganisms present good base for the production of safe osmotically dehydrated products of animal origin.
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Bacterias , Contaminación de Alimentos , Modelos Biológicos , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Beta vulgaris/química , Contaminación de Alimentos/análisis , Contaminación de Alimentos/prevención & control , Melaza/microbiología , Presión OsmóticaRESUMEN
The study investigated an integrated bioprocessing of raw and by-products from sugarcane and dairy industries for production of non-digestible prebiotic and functional ingredients. The low-priced feedstock, whey, molasses, table sugar, jaggery, etc., were subjected to transglucosylation reactions catalyzed by dextransucrase from Leuconostoc mesenteroides MTCC 10508. HPLC analysis approximated production of about 11-14 g L-1 trisaccharide i.e. 2-α-D-glucopyranosyl-lactose (4-galactosyl-kojibiose) from the feedstock prepared from table sugar, jaggery, cane molasses and liquid whey, containing about 30 g L-1 sucrose and lactose each. The trisaccharide was hydrolysed into the prebiotic disaccharide, kojibiose, by employing recombinant ß-galactosidase from Escherichia coli. The enzyme ß-galactosidase achieved about 90% conversion of 2-α-D-glucopyranosyl-lactose into kojibiose. The D-fructose generated by catalytic reactions of dextransucrase was targeted for catalytic transformation into rare sugar, D-allulose (or D-psicose), by treating the samples with Smt3-D-psicose 3-epimerase. The catalytic reactions resulted in the conversion of ~ 25% D-fructose to D-allulose. These bioactive compounds are known to exert a plethora of benefits to human health, and therefore, are preferred ingredients for making functional foods.
Asunto(s)
Metabolismo de los Hidratos de Carbono , Carbohidratos , Industria Lechera , Melaza/microbiología , Saccharum/metabolismoRESUMEN
The industrial utilization of enzymes requires the high yield of enzyme production for the synthesis of polymers by microorganisms. Therefore, it is necessary to optimize different production parameters of levansucrase in order to increase its industrial applications. Zymomonas mobilis KIBGE-IB14 was considered as a promising candidate for the large scale production of levan among wide range of microorganisms. The current investigation is aimed to optimize the production parameters of levansucrase by Z. mobilis KIBGE-IB14 isolated from molasses. The results indicated that bacterial growth as well as enzyme production was greatly influenced by both physical and chemical conditions. It was revealed that high enzyme titers were achieved at 30°C with pH 6.5 after 24 hours of incubation in a modified medium. Moreover, the enzyme exhibited its induction in the presence of sucrose used as a substrate. Thus, the present study demonstrated that newly isolated Z. mobilis KIBGE-IB14 can be used as a plausible producer of levansucrase for industrial applications.