Abstract:It was the objective of the present study to increase the production of glucoamylase by Aspergillus awamori through solid state fermentation, using wheat bran as the main carbon source and (NH 4 ) 2 SO 4 , urea, KH 2 PO 4 , glucose, maltose and starch as additional nitrogen, phosphorus, and carbon sources. The production of glucoamylase is strongly influenced by N and C sources. A 100 % increase was observed when the (NH 4 ) 2 SO 4 was replaced by urea, with C/N = 4.8, using maltose as the additional carbon so… Show more
“…A sharp decline in enzyme activity (7.183±1.201U/ml/min) was observed at pH 6.5. It was due to the fact that the mould required slightly acidic pH for its growth and subsequent enzyme production as reported earlier by Bertolin et al (2003).Figure 2 Effect of initial pH on GGH production by A. oryzae IIB-6. Incubations were carried out for 72 h at 30±2°C and 200 rpm.…”
Section: Resultsmentioning
confidence: 56%
“…It was due to the fact that enzyme production is strongly influenced by the organic carbon and nitrogen sources as reported by Bertolin et al (2003). Furthermore, M3 has an adequate amount of C/N sources compared to M1, M2, M4, and M5.…”
Sixteen different mould cultures viz. Aspergillus, Alternaria, Arthroderma, Trichoderma, Fusarium, Penicillium, Rhizopus and Chochliobolus were isolated from the soil samples of Qatar by serial dilution method. The preliminary screening of isolates was done by selecting initial colonies showing relatively bigger zones of starch hydrolysis on nutrient agar plates. The isolates were then subjected to secondary screening by submerged fermentation (SmF). The 1,4-α-D-glucan glucohydrolase (GGH) activity ranged from 1.906-12.675 U/ml/min. The product yield was analysed in dependence of mycelial morphology, biomass level and protein content. The isolate Aspergillus oryzae llB-6 which gave maximum enzyme production was incubated in M3 medium containing 20 g/l starch, 10 g/l lactose, 8.5 g/l yeast extract, 6 g/l corn steep liquor (CSL), 1.2 g/l MgSO4.7H2O, 1.3 g/l NH4Cl, 0.6 g/l CaCl2.2H2O, pH 5 at 30±2°C and 200 rpm. On the basis of kinetic variables, notably Qp (0.058±0.01a U/g/h), Yp/s (0.308±0.03ab U/g) and qp (0.210±0.032abc U/g fungal biomass/h), A. oryzae IIB-6 was found to be a hyper producer of GGH (LSD 0.0345) compared to A. kawachii IIB-2. A noticeable enhancement in enzyme activity of over 30% was observed (13.917±1.01 U/ml/min) when the process parameters viz. cultural conditions (pH 5, incubation period 72 h) and nutritional requirements (6 g/l CSL, 9.5 g/l yeast extract, 10 g/l starch, 20 g/l lactose) were further optimized using a 2-factorial Plackett-Burman design. The model terms were found to be highly significant (HS, p≤0.05), indicating the potential utility of the culture (dof~3).
“…A sharp decline in enzyme activity (7.183±1.201U/ml/min) was observed at pH 6.5. It was due to the fact that the mould required slightly acidic pH for its growth and subsequent enzyme production as reported earlier by Bertolin et al (2003).Figure 2 Effect of initial pH on GGH production by A. oryzae IIB-6. Incubations were carried out for 72 h at 30±2°C and 200 rpm.…”
Section: Resultsmentioning
confidence: 56%
“…It was due to the fact that enzyme production is strongly influenced by the organic carbon and nitrogen sources as reported by Bertolin et al (2003). Furthermore, M3 has an adequate amount of C/N sources compared to M1, M2, M4, and M5.…”
Sixteen different mould cultures viz. Aspergillus, Alternaria, Arthroderma, Trichoderma, Fusarium, Penicillium, Rhizopus and Chochliobolus were isolated from the soil samples of Qatar by serial dilution method. The preliminary screening of isolates was done by selecting initial colonies showing relatively bigger zones of starch hydrolysis on nutrient agar plates. The isolates were then subjected to secondary screening by submerged fermentation (SmF). The 1,4-α-D-glucan glucohydrolase (GGH) activity ranged from 1.906-12.675 U/ml/min. The product yield was analysed in dependence of mycelial morphology, biomass level and protein content. The isolate Aspergillus oryzae llB-6 which gave maximum enzyme production was incubated in M3 medium containing 20 g/l starch, 10 g/l lactose, 8.5 g/l yeast extract, 6 g/l corn steep liquor (CSL), 1.2 g/l MgSO4.7H2O, 1.3 g/l NH4Cl, 0.6 g/l CaCl2.2H2O, pH 5 at 30±2°C and 200 rpm. On the basis of kinetic variables, notably Qp (0.058±0.01a U/g/h), Yp/s (0.308±0.03ab U/g) and qp (0.210±0.032abc U/g fungal biomass/h), A. oryzae IIB-6 was found to be a hyper producer of GGH (LSD 0.0345) compared to A. kawachii IIB-2. A noticeable enhancement in enzyme activity of over 30% was observed (13.917±1.01 U/ml/min) when the process parameters viz. cultural conditions (pH 5, incubation period 72 h) and nutritional requirements (6 g/l CSL, 9.5 g/l yeast extract, 10 g/l starch, 20 g/l lactose) were further optimized using a 2-factorial Plackett-Burman design. The model terms were found to be highly significant (HS, p≤0.05), indicating the potential utility of the culture (dof~3).
“…Farias et al (2007) mostram que, após um período de 6 horas de sacarificação, ocorre uma redução do potencial sacarificante do malte devido à perda da termoestabilidade das enzimas. A redução da velocidade de hidrólise do amido ocorre em razão das quantidades crescentes de açúcares redutores no meio, repressão conhecida como efeito glicose (Bertolin et al, 2003).…”
Section: Processo De Sacarificação E Fermentação Alcoólicaunclassified
“…No Brasil, existe a perspectiva de produção de álcool a partir de amiláceos, particularmente para produção de álcool para perfumes, para a indústria de bebidas alcoólicas e para a produção de xaropes com alta concentração de glicose, representando um grande avanço tecnológico na industrialização do amido (Bertolin et al, 2003;Biazus et al, 2005).…”
RESUMOObjetivou-se avaliar o potencial de sacarificação do malte de milho para produção de álcool deste cereal. Para tal, foi realizada germinação do grão de milho a 20 ºC por 5 dias. O potencial amilolítico do malte de milho foi otimizado por meio de .
Termos de indexação:Amido, enzimas amilolíticas, fermentação alcoólica e sacarificação.
ABSTRACTThe aim of this research was the production of maize malt and the evaluation of its use for alcohol production. The maize grain was allowed to germinate at 20°C for five days. The amylolitic potential of malt was optimized through a Complete Factorial Planning 2 2 with three central points, where the study variables were the temperature of incubation and the substrate concentration [S]. The sacarification was performed through a Planning of Mixture with three central points, where the study variables were the malt concentration and [S] during six 6 hours. The fermentation was carried out using the best sacarification condition, in a five-liter reactor and a two-liter working volume. The pH was maintained at 4.5 -5.0. The Brix was corrected to 14º. The sterile hydrolyzed product was inoculated with 5.0 g.L -1 Saccharomyces cerevisiae. The system was submitted to two hours of initial aeration (170 L O2 .h -1 ) and kept at 30°C. During the fermentation process, analyses were made to determine the cell concentrations (g.L -1 ), reducing sugars (mg.mL -1 ), alcohol (g.L -1 ) and °Brix. The temperature of incubation and substrate concentration were significant factors (p<0.05) in the determination of the amylolytic potential under the conditions of study utilizing 20% of substrate and incubation at 70°C. The central experiments with 50% malt presented the best kinetic parameters with a volumetric rate of ethanol formation of 2.81 g ethanol .L -1 .h -1 , which correspond to 8.0 ºGL, and a substrate conversion in cells of 0.127g cells .g glucose -1 .
“…Reducing groups released were determined by the DNS method (Miller, 1959) using glucose as a standard. One AMG unit (U) was defined as the amount of enzyme required to produce 1 mmol of glucose per minute in the presence of 4% (w/v) soluble starch solution at 60°C and pH 4.6 (Bertolin et al, 2003). Exo-polygalacturonase (exo-PG) was extracted by placing 1 g of culture material in a flask, adding 9 ml of distilled water, agitating at 100 rpm for 30 minutes at 30ºC and removing debris by filtering through Whatman #41 filter-paper.…”
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