Publications (38)70.94 Total impact
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Article: Bisphenol A degradation in water by ligninolytic enzymes.
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ABSTRACT: Many endocrine disruptor compounds, such as bisphenol A (BPA) are used today and released into the environment at low doses but they are barely degraded in wastewater treatment plants. One of the potential alternatives to effectively degrade endocrine disruptor compounds is based on the use of the oxidative action of extracellular fungal enzymes. The aim of this work is to study the ability of free and encapsulated enzymes (manganese peroxidase, lignin peroxidase and laccase) to degrade BPA. Higher degradation of BPA (90%) by ligninolytic enzymes encapsulated on polyacrylamide hydrogel and pectin after 8h was obtained. The degradation of BPA while using the free enzyme (26%) was lower than the value obtained with encapsulated enzymes. The presence of pectin in the formulation significantly (p>0.05) enhanced the activity of enzymes. Kinetics of BPA degradation showed an increase in Vm, while Km remained constant when enzymes were encapsulated. Hence, encapsulation protected the enzymes from non-competitive inhibition.Chemosphere 05/2013; · 3.21 Impact Factor -
Article: Encapsulation of ligninolytic enzymes and its application in clarification of juice.
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ABSTRACT: The thermal stability, physico-chemical properties and effect on juice clarification of hydrogel formulations of ligninolytic enzymes from Phanerochaete chrysosporium were evaluated. The results showed that enzyme entrapment increase significantly (P<0.05) the thermal stability of enzymes at 4 and 75°C. At 75°C, maximum activity decreased to non detectable values of 7.9% for free laccase, manganese peroxidase (MnP), lignin peroxidase (LiP), respectively; to 94%, 97%, 93% for laccase, MnP and LiP entrapped into Polyacrylamide/pectin, 94%, 98%, 88% for laccase, MnP and LiP encapsulated respectively into polyacrylamide/ gelatine and to 87%, 91%, 87% for laccase, MnP and LiP entrapped, respectively into polyacrylamide/carboxymethylcellulose (CMC). When particle size and viscosity of the formulation increased, enzyme stability increased. The polyphenolic reduction and clarity amelioration in mixed juice of berry and pomegranate was more significant (p>0.05) using encapsulated enzymes treatment than free enzymes. This suggested that enzymatic treatment was efficient for the juice clarification.Food Chemistry 04/2013; 137(1-4):18-24. · 3.65 Impact Factor -
Article: Lignin analysis using microwave digestion.
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ABSTRACT: Lignin quantification in apple pomace residues was carried out using a microwave oven to replace traditional refluxing during the mild acidolysis step to augment the selectivity of this step towards cleavage of lignin-carbohydrate bonds and to reduce the time needed to quantify lignin. The pressure, temperature and time were optimized by response surface methodology and the results were compared to the Klason lignin methodology. Temperature and pressure had a significant positive effect (p < 0.05) on the determination of lignin. However, the time was also significant (p < 0.05) on lignin quantification. The optimal conditions of digestion were: 30 bar, 170 °C for 15 min. The digestion using microwave (lignin content = 33 % w/w) was more accurate (p < 0.05) than the the traditional refluxing (lignin content = 27 % w/w).Biotechnology Letters 07/2012; · 1.68 Impact Factor -
Article: Polyphenolic Antioxidant Mobilization in Apple Pomace by Different Methods of Solid-State Fermentation and Evaluation of Its Antioxidant Activity
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ABSTRACT: An investigation was carried out to understand the changes and mobilization of polyphenolics and the improvement in their antioxidant properties in apple pomace by solid-state fermentation using Generally Recognized as Safe grade fungus, Phanerochaete chrysosporium, by different fermentation techniques, such as flask, tray, and fermentor. β-glucosidase, ligninolytic enzymes activity, and polyphenolic-linked antioxidant activity of apple pomace during solid-state fermentation was studied. During the course of solid-state fermentation, there was an increase in the extractable polyphenolic content (15.53 to 29.28mg of gallic acid equivalents per gram of dry weight (DW)) on the 7th day followed by a decline in the polyphenol content. Antioxidant activity was measured by 1,1-diphenyl-2-picrylhydrazyl radical inhibition system, and the increase in activity (∼35%) was directly proportional to polyphenolic content over the course of solid-state fermentation. After an initial lag phase with little activity, the β-glucosidase activity increased by 6-, 7-, and 6-fold in flask (18.12U/g DW samples), fermentor (44.52U/g of DW sample), and tray fermentation (46.66U/g DW sample) methods, respectively. Both polyphenolics and antioxidant capacity correlated with the increase in the β-glucosidase activity and showed that the enzyme played an important role in the release of polyphenolic aglycones from apple pomace and therefore increased the antioxidant capacity. In addition, ligninolytic enzymes showed a direct correlation with the mobilization and polymerization of polyphenolic content during the solid-state fermentation. KeywordsSolid-state fermentation– Phanerochaete chrysosporium –Apple pomace–Polyphenolic compounds–AntioxidantsFood and Bioprocess Technology 05/2012; · 3.70 Impact Factor -
Article: Parameter optimization for production of ligninolytic enzymes using agro-industrial wastes by response surface method
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ABSTRACT: Lignin and manganese peroxidase (LiP, MnP) and laccase production by Phanerocheate chrysosporium was optimized by response surface methodology for brewery waste and apple pomace. The effect of moisture, copper sulphate, and veratryl alcohol (VA) concentrations on enzyme production was studied. Moisture and VA had significant positive effect on MnP and LiP production and the viability of P. chrysosporium (p < 0.05) and copper sulphate produced a negative effect. However, moisture and copper sulphate had a significant positive (p < 0.05) effect on laccase production, but VA had an insignificant positive effect (p < 0.05). Higher values of MnP, LiP and viability of P. chrysosporium on apple pomace (1287.5 U MnP/gds (units/gram dry substrate), 305 U LiP/gds, and 10.38 Log 10 viability) and brewery waste (792 U MnP/gds and 9.83 Log 10 viability) were obtained with 80% moisture, 3 mmol/kg VA, and 0.5 mmol/kg copper. LiP production in brewery waste (7.87 U/gds) was maximal at 70% moisture, 2 mmol/kg VA, and 1 mmol/kg copper. Higher production of laccase in apple pomace (789 U/gds) and brewery waste (841 U/gds) were obtained with 80% moisture, 3 mmol/kg VA, and 1.5 mmol/kg copper. Thus, moisture along with VA and copper sulphate was pertinent for the production of ligninolytic enzymes and increased cell viability. Keywordsligninolytic enzyme– Phanerocheate chrysosporium –response surface–moisture–inducersBiotechnology and Bioprocess Engineering 04/2012; 16(2):343-351. · 1.28 Impact Factor -
Article: Bio-processing of agro-byproducts to animal feed.
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ABSTRACT: Agricultural and food-industry residues constitute a major proportion (almost 30%) of worldwide agricultural production. These wastes mainly comprise lignocellulosic materials, fruit and vegetable wastes, sugar-industry wastes as well as animal and fisheries refuse and byproducts. Agro-residues are rich in many bioactive and nutraceutical compounds, such as polyphenolics, carotenoids and dietary fiber among others. Agro residues are a major valuable biomass and present potential solutions to problems of animal nutrition and the worldwide supply of protein and calories, if appropriate technologies can be used for their valorization by nutrient enrichment. Technologies available for protein enrichment of these wastes include solid substrate fermentation, ensiling, and high solid or slurry processes. Technologies to be developed for the reprocessing of these wastes need to take account of the peculiarities of individual wastes and the environment in which they are generated, reprocessed, and used. In particular, such technologies need to deliver products that are safe, not just for animal feed use, but also from the perspective of human feeding. This review focuses on the major current applications of solid-state fermentation in relation to the feed sector.Critical Reviews in Biotechnology 03/2012; · 6.47 Impact Factor -
Chapter: Sustainable Solutions for Agro Processing Waste Management: An Overview
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ABSTRACT: Technological revolution in the field of agriculture has tremendously increased the agriculture production. The net impact by the revolution in agriculture has resulted in fast development on food processing industries all over the world. As a result of this rapid development, significant quantities of agricultural products are subjected to processing to make them suitable for consumption, increased storage stability, improved nutrition and sensory quality. Food industrialization has generated large quantity of food products, provided employment to large number of people and uplifted the economic status, at the same time; it generated waste in huge quantities causing environmental pollution. Pollution has not only scientific aspects but also sociological and economical, causing adverse impacts on human beings and its environment. The food wastes can be classified into different categories, such as crop waste and residues; fruits and vegetables by-products; sugar, starch and confectionary industry by-products; oil industry by-products; grain and legumes by-products; distilleries and breweries by-products. Food industry wastes and by-products are geographically scattered comprising large volume and low nutritional value. Consequently, collection, transportation and processing cost of the by-products can exceed the selling price. If we could produce valuable products from food industry by-products through new scientific and technological methods, these by-products could be converted into products with a higher economic value than the main products. Different ways of utilization of by-products from food processing industry can be mainly classified into five categories, such as source for food/feed ingredients, as a carbon source for growing useful microorganisms, as fertilizer by composting, as a source for direct energy generation/biogas production and as a source for high value-added products. This chapter provides a brief discussion on the utilization of agro-processing wastes as a source of nutrients, phytochemicals, and fermentable substrate. KeywordsAgro-processing waste s-Agro by-product s-Nutrients-Phytochemicals-Carbon source09/2011: pages 65-109; -
Article: Extraction and Analysis of Polyphenols: Recent trends
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ABSTRACT: In recent years, there has been an increasing interest in diets rich in fruits and vegetables and this is mostly due to their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. This is mainly due to the presence of bioactive compounds, such as polyphenols, carotenoids, among others. Polyphenols are one of the main classes of secondary metabolites derived from plants offering several health benefits resulting in their use as functional foods. Prior to the use of these polyphenols in specific applications, such as food, pharmaceutical, and the cosmetic industries, they need to be extracted from the natural matrices, then analyzed and characterized. The development of an efficient procedure for the extraction, proper analysis, and characterization of phenolic compounds from different sources is a challenging task due to the structural diversity of phenolic compounds, a complex matrix, and their interaction with other cellular components. In this light, this review discusses different methods of extraction, analysis, and the structural characterization of polyphenolic compounds.08/2011; 31(3):227-249. -
Article: Pomace waste management scenarios in Québec--impact on greenhouse gas emissions.
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ABSTRACT: Fruit processing industries generate tremendous amount of solid wastes which is almost 35-40% dry weight of the total produce used for the manufacturing of juices. These solid wastes, referred to as, "pomace" contain high moisture content (70-75%) and biodegradable organic load (high BOD and COD values) so that their management is an important issue. During the management of these pomace wastes by different strategies comprising incineration, landfill, composting, solid-state fermentation to produce high-value enzymes and animal feed, there is production of greenhouse gases (GHG) which must be taken into account. In this perspective, this study is unique that discusses the GHG emission analysis of agro-industrial waste management strategies, especially apple pomace waste management and repercussions of value-addition of these wastes in terms of their sustainability using life cycle assessment (LCA) model. The results of the analysis indicated that, among all the apple pomace management sub-models for a functional unit, solid-state fermentation to produce enzymes was the most effective method for reducing GHG emissions (906.81 tons CO(2) eq. per year), while apple pomace landfill resulted in higher GHG emissions (1841.00 tons CO(2) eq. per year). The assessment and inventory of GHG emissions during solid-state fermentation gave positive indications of environmental sustainability for the use of this strategy to manage apple pomace and other agricultural wastes, particularly in Quebec and also extended to other countries. The analysis and use of parameters in this study were drawn from various analytical approaches and data sources. There was absence of some data in the literature which led to consideration of some assumptions in order to calculate GHG emissions. Hence, supplementary experimental studies will be very important to calculate the GHG emissions coefficients during agro-industrial waste management.Journal of hazardous materials 06/2011; 192(3):1178-85. · 4.14 Impact Factor -
Article: Enhanced solid-state citric acid bio-production using apple pomace waste through surface response methodology.
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ABSTRACT: Aims: To evaluate the potential of apple pomace (AP) supplemented with rice husk for hyper citric acid production through solid-state fermentation by Aspergillus niger NRRL-567. Optimization of two key parameters, such as moisture content and inducer (ethanol and methanol) concentration was carried out by response surface methodology. Methods and Results: In this study, the effect of two crucial process parameters for solid-state citric acid fermentation by A. niger using AP waste supplemented with rice husk were thoroughly investigated in Erlenmeyer flasks through response surface methodology. Moisture and methanol had significant positive effect on citric acid production by A. niger grown on AP (P < 0·05). Higher values of citric acid on AP by A. niger (342·41 g kg(-1) and 248·42 g kg(-1) dry substrate) were obtained with 75% (v/w) moisture along with two inducers [3% (v/w) methanol and 3% (v/w) ethanol] with fermentation efficiency of 93·90% and 66·42%, respectively depending upon the total carbon utilized after 144 h of incubation period. With the same optimized parameters, conventional tray fermentation was conducted. The citric acid concentration of 187·96 g kg(-1) dry substrate with 3% (v/w) ethanol and 303·34 g kg(-1) dry substrate with 3% (v/w) methanol were achieved representing fermentation efficiency of 50·80% and 82·89% in tray fermentation depending upon carbon utilization after 120 h of incubation period. Conclusions: Apple pomace proved to be the promising substrate for the hyper production of citric acid through solid-state tray fermentation, which is an economical technique and does not require any sophisticated instrumentation. Significance and Impact of the Study: The study established that the utilization of agro-industrial wastes have positive repercussions on the economy and will help to meet the increasing demands of citric acid and moreover will help to alleviate the environmental problems resulting from the disposal of agro-industrial wastes.Journal of Applied Microbiology 02/2011; · 2.34 Impact Factor -
Article: Extraction and analysis of polyphenols: recent trends.
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ABSTRACT: In recent years, there has been an increasing interest in diets rich in fruits and vegetables and this is mostly due to their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. This is mainly due to the presence of bioactive compounds, such as polyphenols, carotenoids, among others. Polyphenols are one of the main classes of secondary metabolites derived from plants offering several health benefits resulting in their use as functional foods. Prior to the use of these polyphenols in specific applications, such as food, pharmaceutical, and the cosmetic industries, they need to be extracted from the natural matrices, then analyzed and characterized. The development of an efficient procedure for the extraction, proper analysis, and characterization of phenolic compounds from different sources is a challenging task due to the structural diversity of phenolic compounds, a complex matrix, and their interaction with other cellular components. In this light, this review discusses different methods of extraction, analysis, and the structural characterization of polyphenolic compounds.Critical Reviews in Biotechnology 11/2010; 31(3):227-49. · 6.47 Impact Factor -
Article: Methane production potential (B0) of swine and cattle manures--a Canadian perspective.
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ABSTRACT: Canada's agricultural emissions accounted for 60 Mt or 8% of national greenhouse gas (GHG) emissions in 2007. The estimation of CH4 emission factor (B0) from manure management systems in Canada is prone to uncertainty owing to lack of B0 values for Canadian conditions. Therefore, in this study, manure samples from six Canadian animal farms, two each of swine, beef and dairy cattle, were investigated in order to estimate their methane production potential (B0). The ultimate anaerobic biodegradability was measured with ISO standard batch fermentation. The extent of biodegradation of the manure samples with or without sodium benzoate was always greater than 60% and hence showed no inhibitory effect on methane production by the manure. The impact of use of antibiotics in the animal feed on methane production was also considered; however, no inhibitory effect on methane production could be observed. The plateau of methane production in all cases was achieved by 63 d of anaerobic digestion process and the final pH was within 6-8. The calculated B0 were in the range of 0.47-0.42, 0.21-0.19 and 0.35-0.30 for swine, beef cattle and dairy cattle, respectively. The uncertainties associated with B0 values were +/- 9% for swine, +/- 3% for beef cattle and, +/- 6 and +/- 2% for dairy cows.Environmental Technology 11/2010; 31(12):1371-9. · 1.41 Impact Factor -
Article: Methane production potential (B0) of swine and cattle manures – A Canadian perspective
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ABSTRACT: Canada’s agricultural emissions accounted for 60 Mt or 8% of national greenhouse gas (GHG) emissions in 2007. The estimation of CH4 emission factor (B0) from manure management systems in Canada is prone to uncertainty owing to lack of B0 values for Canadian conditions. Therefore, in this study, manure samples from six Canadian animal farms, two each of swine, beef and dairy cattle, were investigated in order to estimate their methane production potential (B0). The ultimate anaerobic biodegradability was measured with ISO standard batch fermentation. The extent of biodegradation of the manure samples with or without sodium benzoate was always greater than 60% and hence showed no inhibitory effect on methane production by the manure. The impact of use of antibiotics in the animal feed on methane production was also considered; however, no inhibitory effect on methane production could be observed. The plateau of methane production in all cases was achieved by 63 d of anaerobic digestion process and the final pH was within 6–8. The calculated B0 were in the range of 0.47−0.42, 0.21−0.19 and 0.35−0.30 for swine, beef cattle and dairy cattle, respectively. The uncertainties associated with B0 values were ± 9% for swine, ± 3% for beef cattle and, ± 6 and ± 2% for dairy cows.Environmental Technology 11/2010; 31(12):1371-1379. · 1.41 Impact Factor -
Article: Entomotoxicity, protease and chitinase activity of Bacillus thuringiensis fermented wastewater sludge with a high solids content.
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ABSTRACT: This study investigated the production of biopesticides, protease and chitinase activity by Bacillus thuringiensis grown in raw wastewater sludge at high solids concentration (30 g/L). The rheology of wastewater sludge was modified with addition of Tween-80 (0.2% v/v). This addition resulted in 1.6 and 1.3-fold increase in cell and spore count, respectively. The maximum specific growth rate (micro(max)) augmented from 0.17 to 0.22 h(-1) and entomotoxicity (Tx) increased by 29.7%. Meanwhile, volumetric mass transfer coefficient (k(L)a) showed marked variations during fermentation, and oxygen uptake rate (OUR) increased 2-fold. The proteolytic activity increased while chitinase decreased for Tween amended wastewater sludge, but the entomotoxicity increased. The specific entomotoxicity followed power law when plotted against spore concentration and the relation between Tx and protease activity was linear. The viscosity varied and volume percent of particles increased in Tween-80 amended wastewater sludge and particle size (D(50)) decreased at the end of fermentation. Thus, there was an increase in entomotoxicity at higher suspended solids (30 g/L) as Tween addition improved rheology (viscosity, particle size, surface tension); enhanced maximum growth rate and OUR.Bioresource technology 06/2009; 100(19):4317-25. · 4.25 Impact Factor -
Article: Wastewater sludges as novel growth substrates for rearing codling moth larvae
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ABSTRACT: Codling moth (CM), Cydia pomonella (L) is a pest of numerous fruit species and is also used as a host for baculovirus (granulovirus) and hence the high rate production of CM is important for their biological control. In this research, different wastewater residues from cheese industry, starch industry and municipal wastes (eight different types of larval diets) were investigated as potential substitutes for protein ingredient (principal component) of insect diet. CM larvae were produced with 65–75% survival rate and were healthy as observed under the microscope. Hence, use of cheaper alternatives in the diet derived from agriculture and/or municipal wastes was feasible. Moreover, the preparation steps involved, sterilization, mixing and homogenization and hence the simplicity of these steps makes it practical to scale-up the diet to industrial scale in future. There was no contamination all during the process development. Dryness of all larval diets increased with time, however, even after 26 days, the dryness was ≤18% which is an acceptable norm. Weight, length and diameter of CM larvae was higher when 50% of protein was replaced by cheese industry sludge and corresponded to 145 ± 5, 174 ± 5, and 103 ± 3% increase, respectively. Cheese industry sludge gave highest fecundity of 340 eggs/adult/g of larval diet and the values were higher for other alternative larval diets too. Hence, CM insect diet can be developed using alternative protein substitutes (wastewater residues) is feasible, by adopting simplified scheme with scope for industrial scale-up.World Journal of Microbiology and Biotechnology 11/2008; 24(12):2849-2857. · 1.53 Impact Factor -
Article: Bacillus thuringiensis fermentation of wastewater and wastewater sludge--presence and characterization of chitinases.
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ABSTRACT: This study investigated the presence of chitinases in Bacillus thuringiensis ssp kurstaki HD-1 (Bt) fermented broths of wastewater sludge (non-hydrolyzed and hydrolyzed); starch industry wastewater and soyameal. Chitinase activity was absent in soyameal and present in others. Chitinase demonstrated peaks at pH 4.0 and temperatures 40 and 50 degrees C with higher activity between pH 4-5 and 10-11. The chitinase band on SDS-PAGE was found to be between 36 and 45 kDa for non-hydrolyzed (NH) and hydrolyzed sludge (TH) and starch industry wastewater. The chitinase profile during fermentation showed peaks at 15 and 30 h for non-hydrolyzed and hydrolyzed sludge and 15 and 24 h for starch industry wastewater. Chitinase retained 96-99 % activity after two weeks incubation at room temperature and pH 4. Bioassays with supplementation of Bt chitinases showed 1.2 fold increase in entomotoxicity of wastewater sludge and a small increase in starch industry wastewater. This study sheds light on production of Bt chitinases in alternative media which will have a long term effect on entomotoxicity of these formulations.Environmental Technology 03/2008; 29(2):161-70. · 1.41 Impact Factor -
Article: Starch industry wastewater as a substrate for antagonist, Trichoderma viride production.
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ABSTRACT: Starch industry wastewater was investigated to assess and improve its potential as a raw material for the conidia production of biocontrol fungi, Trichoderma viride. The wastewater was tested with and without supplements of glucose, soluble starch, meat peptone and probable conidiation inducer chemicals in shake flask culture. Addition of complex carbon source (soluble starch, 1% and 2% w/v) produced maximum conidia ( approximately 3.02 and 4.2 x 10(10)CFU/mL, respectively). On the other hand, glucose addition as a simpler carbon source was either ineffective or, reduced conidia production (from 1.6 x 10(8) in control to 3.0 x 10(7)CFU/mL in 5% w/v glucose supplement). Supplement of nitrogen source showed a small increase of conidia concentration. Propionic, maleic and humic acids, EDTA, pyridine, glycerol and CaCO(3) were examined as probable conidiation inducers and showed effect only on initial rate of conidiation with no increase in final conidia concentration. Intra and extracellular ATP correlation with spore production showed dependence on growth media used and conidia concentration at the end of fermentation. Addition of carbon and nitrogen sources showed an increase in protease activity (from 0.4985 to 2.43 IU/mL) and entomotoxicity (from 10448 to 12335 spruce budworm unit (SBU)/microL). Entomotoxicity was improved by 11% in fermenter over shake flask when starch industry wastewater was supplemented with meat peptone.Bioresource Technology 09/2007; 98(11):2154-62. · 4.98 Impact Factor -
Article: Bacillus thuringiensis fermentation of hydrolyzed sludge--rheology and formulation studies.
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ABSTRACT: Rheology of Bacillus thuringiensis fermentation of hydrolyzed sludge was investigated in bench scale fermenter. Stable liquid formulations were developed and optimized for two-year based studies comprising various physical/chemical (viscosity, particle size, corrosion and suspendibility) and biological (microbial contamination, viable spores and entomotoxicity) parameters at different pHs and temperatures. The hydrolyzed sludge depicted non-Newtonian and pseudoplastic behaviour during fermentation with 90% to 96% confidence of fits into Casson, Power and IPC paste models. Higher values of consistency and flow index during exponential growth and stationary phase, respectively, affected downstream processing. The power law was also followed by stable formulations. Sorbitol, sodium monophosphate and sodium metabisulfite (2.2:1:1) as suspending agents produced suspendibility ranging from 69% to 94%. The stable formulation (FH-4) comprising sorbitol, sodium monophosphate and sodium metabisulfite deteriorated at pHs 6, 6.5 and temperatures, 40 and 50 degrees C, with no signs of corrosion and microbial contamination. The viscosity of FH-4 formulations decreased with shear rate which could improve handling and consequent spraying.Chemosphere 04/2007; 67(4):674-83. · 3.21 Impact Factor -
Article: Pre-treatment of wastewater sludge--biodegradability and rheology study.
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ABSTRACT: This study investigates the changes in biodegradability, rheology and metal concentration of wastewater sludge--non-hydrolyzed (raw), sterilized, and hydrolyzed (thermal alkaline pre-treatment) at total solids concentration from 10-50 g l(-1) to ascertain the bioavailability of nutrients for subsequent fermentation. The dissolved solids concentration increased linearly with total solids. Irrespective of the wastewater sludge (raw or, pre-treated), percentage biodegradability in terms of total solids (26.5-44.5%), total COD (25.8-56.5%) and dissolved solids (41.9-66.9%) was maximum around 20 g l(-1) solids concentration. The pseudoplasticity of sludge decreased (consistency index decreased from 895.1 to 5.2 and flow behaviour index increased from 0.28 to 0.88, for all sludge types) with pre-treatment and increased with total solids concentration. The pre-treated sludge, namely, sterilized and hydrolyzed sludge showed higher microbial growth (1-2 log cycles increase in comparison to raw sludge) suggesting their susceptibility to microbial degradation. The C:N ratio decreased with pre-treatment (raw sludge > sterilized > hydrolyzed) during biodegradation. Although the metal concentration increased in incubated hydrolyzed sludge, the final concentration was within the regulatory norms for agriculture application. Thus, pretreatment of sludge resulted in increase in biodegradability making it an excellent proponent for fermented value-added products.Environmental Technology 03/2007; 28(3):273-84. · 1.41 Impact Factor -
Article: Dissolved oxygen as principal parameter for conidia production of biocontrol fungi Trichoderma viride in non-Newtonian wastewater.
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ABSTRACT: Dissolved oxygen (DO) concentration was selected as a principal parameter for translating results of shake flask fermentation of Trichoderma viride (biocontrol fungi) to a fermenter scale. All fermentations were carried out in a 7.5 l automated fermenter with a working volume of 4 l. Fermentation performance parameters such as volumetric oxygen transfer coefficient (k (L) a), oxygen uptake rate (OUR), rheology, conidia concentration, glucose consumption, soluble chemical oxygen demand, entomotoxicity and inhibition index were measured. The conidia concentration, entomotoxicity and inhibition index were either stable or improved at lower DO concentration (30%). Variation of OUR aided in assessing the oxygen supply capacity of the fermenter and biomass growth. Meanwhile, rheological profiles demonstrated the variability of wastewater during fermentation due to mycelial growth and conidiation. In order to estimate power consumption, the agitation and the aeration requirements were quantified in terms of area under the curves, agitation vs. time (rpm h), and aeration vs. time (lpm h). This simple and novel strategy of fermenter operation proved to be highly successful which can be adopted to other biocontrol fungi.Journal of Industrial Microbiology and Biotechnology 12/2006; 33(11):941-52. · 2.73 Impact Factor
Top co-authors
Top Journals
Institutions
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2011–2012
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Institut de recherche et de développement en agroenvironnement
Québec, Quebec, Canada
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2010
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Université du Québec
Québec, Quebec, Canada
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2005
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Institut national de la recherche scientifique
Québec, Quebec, Canada
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