β-fructofuranosidase (invertase) and β-D-fructosyltransferase (FTase) are enzymes used in industrial processes to hydrolyze sucrose aiming to produce inverted sugar syrup or fructooligosaccharides. In this work, a black Aspergillus sp. PC-4 was selected among six filamentous fungi isolated from canned peach syrup which were initially screened for invertase production. Cultivations with pure carbon sources showed that invertase and FTase were produced from glucose and sucrose, but high levels were also obtained from raffinose and inulin. Pineapple crown was the best complex carbon source for invertase (6.71 U/mL after 3 days of cultivation) and FTase production (14.60 U/mL after 5 days of cultivation). Yeast extract and ammonium chloride nitrogen sources provided higher production of invertase (6.80 U/mL and 6.30 U/mL, respectively), whereas ammonium nitrate and soybean protein were the best nitrogen sources for FTase production (24.00 U/mL and 24.90 U/mL, respectively). Fermentation parameters for invertase using yeast extract were YP/S = 536.85 U/g and PP = 1.49 U/g/h. FTase production showed values of YP/S = 2,627.93 U/g and PP = 4.4 U/h using soybean protein. The screening for best culture conditions showed an increase of invertase production values by 5.10-fold after 96 h cultivation compared to initial experiments (fungi bioprospection), while FTase production increased by 14.60-fold (44.40 U/mL) after 168 h cultivation. A. carbonarius PC-4 is a new promising strain for invertase and FTase production from low cost carbon sources, whose synthesized enzymes are suitable for the production of inverted sugar, fructose syrups, and fructooligosaccharides.
Research background. Microbial β-fructofuranosidases are widely employed in food industry to produce inverted sugar or fructooligosaccharides. In this study, a newly isolated Aspergillus carbonarius PC-4 strain was used to optimize the β-fructofuranosidase production under a cost-effective process and the sucrose hydrolysis was evaluated to produce inverted sugars.
Experimental approach. Optimization of nutritional components of culture medium was carried out using Simplex Lattice mixture design for 72 h and 120 h at 28 ˚C. One-Factor-at-a-time methodology was used to optimize the physicochemical parameters. Crude enzyme was used for sucrose hydrolysis at different concentrations.
Results and conclusions. The optimized condition of enzyme production was pineapple crown waste (1.3 %, m/V) and yeast extract (0.3 %, m/V) for 72 h (9.4 U/mL), obtaining R² 91.85 %, R² adjusted 85.06 %, highest F value (13.52) and low p-value (0.003). One-factor-at-a-time used for optimizing the physicochemical conditions showed optimum temperature (20 ˚C), pH (5.5), agitation (180 rpm) and time-course (72 h) with an increase of 3.0-folds for enzyme production. The invertase-induced sucrose hydrolysis showed the maximum yield (3,451.7 µmols of reducing sugars) using 10 % of initial sucrose concentration. Higher sucrose concentrations caused inhibition of invertase activity, possibly due to saturation of substrate or formation of sucrose aggregates making it difficult for the enzyme to access sucrose molecules within the created clusters. So, a cost-effective method was developed for the invertase production using agroindustrial waste and the enzyme produced can be used efficiently for inverted sugar production at high sucrose concentration.
Novelty and scientific contribution. This study presents an efficient utilization of pineapple crown wastes to produce invertase by a newly isolated Aspergillus carbonarius PC-4 strain. This enzyme exhibited a good potential for invert sugar production at high initial sucrose concentration, which is interesting for industrial applications.
This study aimed to optimize the production of xylanase, under submerged conditions using Fusarium oxysporum. Firstly, it was carried out the selection of the best source of carbon from agricultural waste, such as soybean husk, cassava peel, pineapple crown, corn straw, rice husk, bacaba, barley bagasse and, corncob. They were milled and sieved with a maximum granulation of 1 mm. The cultures were carried out by 132 hours 30 °C and 180 rpm. Among the agroindustrial residues, corn straw was the one that stood out with a greater enzymatic activity of 12.6 U/mL. In the second step, it was used Plackett-Burman design to screen the nutrients sources important to xylanase production. Thus, independent variables significant were urea and MgSO4. These variables selected by Plackett-Burman were then used in a Central Composite Rotational Design present activity of 26.6 U/mL and the predicted was 34.5 U/mL. So, the xylanase production by F. oxysporum can be optimize using corn straw, a low-cost waste found in large quantities.
As intoxicações alimentares são consideradas um dos maiores problemas de saúde pública do mundo. Principalmente pelo consumo de alimentos contaminados com microrganismos patogênicos e suas toxinas. O Bacillus cereus é uma bactéria atuante na deterioração dos alimentos e está associada à produção de enterotoxina. O presente estudo teve como objetivo demonstrar a importância do Bacillus cereus através do entendimento da sua epidemiologia, sintomatologia e dos fatores de virulência das toxinas emética e diarréica, bem como formas para evitar a intoxicação e os tratamentos para prevenção. Foram estudados vários casos de intoxicação em que a presença do Bacillus cereus foi detectada em alimentos, equipamentos e utensílios, mostrando que são fontes potenciais de transmissão do microrganismo. Foi evidenciado a necessidade de aprimoramento das notificações de surtos alimentares visando contribuir na diminuição da chance de novas ocorrências de toxinfecções. A inocuidade dos alimentos é de extrema importância para a saúde da população tornando-se necessária a implantação e intensificação de medidas de controle na produção, armazenamento e higienização correta dos equipamentos.
The aim of this work was to evaluate the use of different agro-industrial residues for the production of xylanase by Aspergillus sp. ART 100.1, as well as analyzing the biochemical properties of the enzyme. Agroindustrial residues malt bagasse, pineapple crown, açaí bagasse and soybean husk present in large quantities in the Tocantins region were used to evaluate the production of xylanase. Cultivation conditions for xylanase production were evaluated in submerged and solid-state cultivation. The highest production of xylanase in submerged cultivation was obtained using soybean husk residue (23.60 U/mL), while, for solid-state cultivation conditions, the highest production of xylanase was obtained with malt bagasse (110.00 U/g). The effect of additives to the culture medium was also evaluated, with the best result for the use of the xylose additive in the pineapple crown in solid-state cultivation. The enzyme produced in solid-state cultivation was characterized in terms of pH and temperature. The optimum activity pH was observed at 5.0 and for temperature at 55 °C. The xylanase was stable in a pH range between 4 and 5 and retained 50% of its activity at 45 °C after 110 minutes. The Aspergillus sp. ART 500.1 presents potential for the production of xylanase using agro-industrial residues, enabling the development of bioprocesses for the scaling of production.
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