Invertase, glucose oxidase and catalase for converting sucrose to fructose and gluconic acid through batch and membrane-continuous reactors

Conversion of sucrose into fructose and gluconic acid using invertase, glucose oxidase and catalase was studied by discontinuous (sequential or simultaneous addition of the enzymes) and continuous (simultaneous addition of the enzymes in a 100 kDa-ultrafiltration membrane reactor) processes. The following parameters were varied: concentration of enzymes, initial concentration of substrates (sucrose and glucose), pH, temperature and feeding rate (for continuous process). The highest yield of conversion (100%) was attained through the discontinuous (batch) process carried out at pH 4.5 and 37 ºC by the sequential addition of invertase (14.3 U), glucose oxidase (10,000 U) and catalase (59,000 U).Neste trabalho estudou-se a conversão da sacarose em frutose e ácido glicônico, usando as enzimas invertase, glicose oxidase e catalase, através do emprego de processo descontínuo (com adição sequencial ou simultânea das enzimas) e contínuo (adição simultânea das enzimas em reator com membrana acoplado à membrana de ultrafiltração de 100 kDa). Os parâmetros variados foram: a concentração das enzimas, a concentração inicial dos substratos (sacarose e glicose), o pH, a temperatura e a vazão específica de alimentação (processo contínuo). Obteve-se rendimento de 100%, quando a conversão foi conduzida por processo descontínuo em pH 4,5 e a 37 ºC com adição seqüencial das enzimas invertase (14,3 U), glicose oxidase (10.000 U) e catalase (59.000 U)

ESolvent-free, enzyme-catalyzed biodiesel production from mango, neem, and shea oils via response surface methodology

Mango, neem and shea kernels produce non-conventional oils whose potentials are not fully exploited. To give an added value to these oils, they were transesterified into biodiesel in a solvent-free system using immobilized enzyme lipozyme from Mucor miehei. The Doehlert experimental design was used to evaluate the methyl ester (ME) yields as influenced by enzyme concentration—EC, temperature—T, added water content—AWC, and reaction time—RT. Biodiesel yields were quantified by (1)H NMR spectroscopy and subsequently modeled by a second order polynomial equation with interactions. Lipozyme enzymes were more tolerant to high temperatures in neem and shea oils reaction media compared to that of mango oil. The optimum reaction conditions EC, T, AWC, and RT assuring near complete conversion were as follows: mango oil 7.25 %, 36.6 °C, 10.9 %, 36.4 h; neem oil EC = 7.19 %, T = 45.7 °C, AWC = 8.43 %, RT = 25.08 h; and shea oil EC = 4.43 %, T = 45.65 °C, AWC = 6.21 % and RT = 25.08 h. Validation experiments of these optimum conditions gave ME yields of 98.1 ± 1.0, 98.5 ± 1.6 and 99.3 ± 0.4 % for mango, neem and shea oils, respectively, which all met ASTM biodiesel standards

Treatment of turnip juice wastewater by electrocoagulation/electroflotation and electrooxidation with aluminum, iron, boron-doped diamond, and graphite electrodes

The significant increase in the turnip sector has brought a wastewater problem that needs to be managed. In this study, turnip juice wastewater treatment was studied using the electrocoagulation/electroflotation and electrooxidation processes. Independent process parameters such as electrode type (aluminum-aluminum, iron-iron, boron-doped diamond-platinum and graphite-platinum), current density (25-100 A/m(2)) and retention time (15-180 min) were investigated for the optimization of treatment conditions. Removal efficiencies of chemical oxygen demand and total phenol were studied. It was determined that the optimum removal efficiencies in both electrocoagulation/electroflotation and electrooxidation processes were the same under the conditions of 100 A/m(2) current density, pH 5.4, and 45 min reaction time. Here, 100% removal efficiencies were achieved for both chemical oxygen demand and total phenol. The operating cost of the electrocoagulation/electroflotation process was calculated as 1.58 $/m(3), while it was determined as 0.61$/m(3) for electrooxidation for the optimum removal parameters. It is seen in laboratory scale test results that electrocoagulation/electroflotation and electrooxidation processes are applicable/feasible for the treatment of turnip juice wastewater

Biosorption characteristics of methylene blue dye by two fungal biomasses

International audienceA novel approach has been tried to use both Aspergillus carbonarius (AC) and Penicillium glabrum (PG) fungi for the first time to remove methylene blue (MB) from aqueous solutions. The biosorption was favoured using a biosorbent concentration of 0.33 g/L at pH 8.2. Biosorption kinetics were evaluated for different dye concentrations (5–25 mg/L). The resulting biosorbent was characterised by scanning electron microscopy (SEM), X-ray diffractometer and Fourier transformer infrared spectroscopy (FTIR) techniques. The maximum biosorption capacities of AC and PG for MB were 21.88 mg/g and 16.67 mg/g, respectively at 30°C. The results suggested that A. carbonarius and P. glabrum could be used as biosorbents for the effective removal of methylene blue from dye wastewater in terms of biosorption capacity, availability and low cost