36 research outputs found
A Study on the Torrefaction of Rice Husk as an Attempt to Enhance Its Energy Content
87-90Torrefaction refers to the thermal and chemical treatment of organic substances (at atmospheric pressure, between 200–300°C, under inert conditions). The objective of this study is to torrefy the rice husk of Ethiopian origin, after a pretreatment with dilute sulfuric acid in order to enhance its energy density. The torrefaction temperature, holding time, and acid concentration investigated in this study were (200, 250, and 300°C), (20, 40, and 60 min) and (0.75, 1.50, and 2.25 g/L), respectively. Box-Behnken experimental Design (BBD) was applied for optimization using Design-Expert ® Version 7 software (Stat-Ease Inc., Minnesota, United States)
Lactic acid production from Brewer’s Spent Grain by Lactobacillus plantarum ATCC 8014
610-613The objective of this research was to produce lactic acid from Brewery Spent Grain using Lactobacillus plantarum ATCC 8014. The production was carried out in four main stages, including the pretreatment, hydrolysis, fermentation and recovery of lactic acid. Box Behnken Design (BBD) (Design expert® 7 software) was used to investigate the effect of temperature (115–130°C), reaction time (25–35 min) and acid concentration (1.5–2.0 M) during the hydrolysis. Fermentation of the hydrolyzate was performed at 35°C, pH 5.0–5.5 and 200 rpm for 72 h. Optimization results proved the suitability of BSG to be used as a feedstock for the lactic acid production
A Study on the Torrefaction of Rice Husk as an Attempt to Enhance Its Energy Content
Torrefaction refers to the thermal and chemical treatment of organic substances (at atmospheric pressure, between 200–300°C, under inert conditions). The objective of this study is to torrefy the rice husk of Ethiopian origin, after a pretreatment with dilute sulfuric acid in order to enhance its energy density. The torrefaction temperature, holding time, and acid concentration investigated in this study were (200, 250, and 300°C), (20, 40, and 60 min) and (0.75, 1.50, and 2.25 g/L), respectively. Box-Behnken experimental Design (BBD) was applied for optimization using Design-Expert ® Version 7 software (Stat-Ease Inc., Minnesota, United States)
OPTIMIZATION OF MEDIUM COMPONENTS FOR ANTIBACTERIAL METABOLITE PRODUCTION FROM MARINE STREPTOMYCES SP. PUA2 USING RESPONSE SURFACE METHODOLOGY
Objective: The present study is an attempt to optimize the fermentation conditions for the antibacterial compound production from a newly isolated marine Streptomyces strain PUA2 by adopting response surface methodology as the statistical tool.
Methods: Prior to using the Response Surface Methodology, Plackett Burmann (PB) design was used to explore the effect of variables on the antibacterial compound production. In PB method, high and low values were assigned for the eight variables viz., glucose, glycerol, soybean meal, manganese chloride, calcium carbonate, peptone and pH. Calcium carbonate and peptone were used as dummy variables. Based on the results of combined effects glycerol, soybean meal, manganese chloride and pH were investigated by 24 full-factorial central composite design.
Results: The results of PB method showed the significant effect of glycerol, soybean meal, manganese chloride and pH on the antibacterial compound production. The results of ANOVA and regression of second order model showed that the linear effects of glycerol and manganese chloride and cross products effects of manganese chloride and pH were more significant. All the critical variables having greatest effect on the production of antibacterial compound from marine Streptomyces species PUA2. Optimization of process parameters resulted in increase in antibacterial activity from 7 mm to 14 mm.
Conclusion: The factors optimized in the present study were useful for the increased production of antibacterial metabolite from Streptomyces sp PUA2. The result confirms the feasibility of medium optimization to improve antibiotic production
Optimization and Kinetics of Cellulase Immobilization on Modified Chitin Using Response Surface Methodology
This study was aimed at investigating the immobilization of Aspergillus nidulans cellulase onto modified chitin (MC). The effects of contact time, cellulase concentration, MC dosage, temperature and agitation rate for maximum immobilization percentage and optimum immobilization capacity have been investigated by response surface methodology (RSM) on the basis of a five-level, five-factor central composite design (CCD). The equilibrium nature of the immobilization was described by the Langmuir and Freundlich isotherms. The kinetic data were tested using the first-order and pseudo-second-order kinetic models. The results of thermodynamic investigations indicate spontaneity (ΔG 0 0) and irreversibility (ΔS 0 > 0) for the sorption process. At 120 rpm, 304.6 K, 23.3 min, 1.12 mg of MC immobilized 18.51 mg/g of cellulase from an initial solution concentration of 16.34 mg/mℓ with a retention of 70% of the native cellulase activity up to 10 cycles in batch hydrolysis experiments. Under optimized conditions, immobilized cellulase had a higher K m value (0.83 mM) and a lower V max value (38.2 μmol/min) compared with the free cellulase (0.62 mM and 48.92 μmol/min, respectively), indicating the affinity of cellulase for the MC matrix
Response Surface Methodology for the Evaluation and Comparison of Cellulase Production by Aspergillus nidulans SU04 and Aspergillus nidulans MTCC344 Cultivated on Pretreated Sugarcane Bagasse
Response surface methodology (RSM) was used to optimize the conditions for the production of endo β-1,4 glucanase – a component of cellulase by Aspergillus nidulans SU04 and Aspergillus nidulans MTCC344 under solid state fermentation, using pretreated bagasse as chief substrate. A four-factor-five-level central composite design was employed for the experimental design. The endo β-1,4 glucanase produced during the bioconversion of cellulose to glucose by these strains were strongly dependent on the NaOH pretreatment given to bagasse before hydrolysis. Maximum cellulase activity was
32.59 U g–1 and 28.96 U g–1 (CMCase) for A.nidulans SU04 and A. nidulans MTCC344 respectively. The optimum conditions for cellulase production are 15 mm bagasse bed height, 60 % moisture content, pH 5 and temperature 40 °C in the solid state fermenter.
A. nidulans MTCC344 and A. nidulans SU04 were able to hydrolyze pretreated sugarcane bagasse completely after 15 days and 6 days of incubation with significant endo β-1,4 glucanase activities. The results of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) of bagasse showed structural changes through pretreatment, in favor of enzymatic hydrolysis. A. nidulans SU04 was found to be highly efficient compared to A. nidulans MTCC344 in terms of endoglucanase, exoglucanase and β-glucosidase activities
Optimization of cellulase synthesis by RSM and evaluation of ethanol production from enzymatically hydrolyzed sugarcane bagasse using <i>Saccharomyces cerevisiae</i>
353-359This
study presents ethanol production from enzymatically hydrolyzed sugarcane
bagasse using Saccharomyces cerevisiae.Response
surface methodology (RSM) was used to optimize conditions for the production of
endo b-1, 4 glucanase component of cellulase using Aspergillus
nidulans MTCC344 under solid state condition,
employing pretreated bagasse as chief substrate. Cellulase thus produced was
utilized for hydrolyses of pretreated bagasse resulting in soluble sugars. FTIR
and XRD of bagasse
showed
structural changes through pretreatment, in favor of enzymatic hydrolysis
during cellulase production. Ethanol produced was found to be strongly
dependent on pretreatment given, hydrolysis and fermentation conditions