Reducing sugars production from corncobs: a comparative study of chemical and biotechnological methods.

Two commonly used chemical pretreatment processes, sulphuric acid, and sodium hydroxide, were tested to provide comparative performance data. A connection between solid to liquid ratio (S/L) and sugars released was observed with an increase in S/L ratio between 0.02 and 0.2. Enzymatic digestibility of 1 M of NaOH-pretreated corncobs were released 210.7 mg ml(-1) of sugars. Further, compared with different concentrations of acid pretreatments at 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.5 M concentrations, sodium hydroxide pretreatment of corncob substantially increased accessibility and digestibility of cellulose. Another additional observation made was whole-cell and crude enzymatic hydrolysis of different concentrations of acid and NaOH (0.05, 0.1, 0.25 M)-treated materials released lower amount of sugars compared with the sugars released (310.9 mg ml(-1)) with whole-cell hydrolysis of 1 M of NaOH-treated corncobs. NaOH-pretreated corncobs contained higher content of sugars and which is more suitable for production of reducing sugars.

Simultaneous pretreatment and sacchariffication of rice husk by Phanerochete chrysosporium for improved production of reducing sugars.

Phanerochete chrysosporium, the white-rot fungus, (a best source for lignolytic enzymes system) was used in the biological pretreatment of rice husk for reducing sugars production. Usually reducing sugar production through biochemical process involves two steps: solid state fermentation (SSF) of fungal pretreatment for delignification, subsequently pretreated biomass subjected to enzymatic hydrolysis. During the fungal pretreatment of rice husk for reducing sugar production along with cellulase and xylanse, the activities of lignin degradation-related enzymes such as lignin peroxidases (LiP), GLOX (glyoxidase), and aryl alcohol oxidases (AAO), were observed. The fungal pretreated rice husk produced highest (895.9 mg/ml/2g of rise husk) reducing sugars on 18th day of fungal treatment. This method may be good alternative to avoid operational costs associated with washing and the removal of inhibitors during the conventional pretreatment methods.

Mixing of acid and base pretreated corncobs for improved production of reducing sugars and reduction in water use during neutralization.

Pretreatment of biomass for bioethanol production makes it necessary to use large amounts of water for removing inhibitors and neutralization. In order to reduce water usage, separate batches of corncobs were hydrolyzed in 1M NaOH and 0.05 M H(2)SO(4), respectively, and the hydrolysis products were mixed to achieve a pH of 7. This approach lowered water usage by 10-fold compared with neutralization by distilled and recycling wash water. Mixing of the pretreated biomasses (121°C, 20 min) increased release of reducing sugars during enzymatic hydrolysis with cellulases (38.49 FPU(IU)) produced by Phanerochaete chrysosporium NCIM 1106 by 2- and 15-fold compared with the sugars released from the unmixed NaOH- and H(2)SO(4)-treated corncobs, respectively. Enzymatic hydrolysis (EH, cell free extract) of the mixed material released 395.15 mg/ml of sugars during 48 h, slightly less than what was achieved by microbial hydrolysis (whole cell hydrolysis), 424.50mg after 120 h.

Antimicrobial activities of neo- and 1-epineo-isoshinanolones from Plumbago zeylanica roots.

CONTEXT: The roots of Plumbago zeylanica Linn. (Plumbaginaceae) are reputed to have a wide spectrum of therapeutic properties in the Ayurvedic system of medicine. They are useful in curing many ailments such as skin diseases, diarrhea, plague and leprosy. OBJECTIVE: The study was aimed at isolating, separating and evaluating the antimicrobial properties of compounds such as neoisoshinanolone and 1-epineo-isoshinanolone from the roots of P. zeylanica. MATERIALS AND METHODS: The crude petroleum ether extract of roots of P. zeylanica was subjected to repeated chromatographic techniques to separate compounds 2 and 3 along with plumbagin. Structure elucidation was carried out using nuclear magnetic resonance (NMR), infra red (IR) and mass spectroscopy. The serial dilution method was used to test antimicrobial activities and their minimum inhibitory concentration (MIC) expressed in microg/mL. RESULTS: 1-Epineo-isoshinanolone is more active with a MIC of 12.5-25 microg/mL whereas neoisoshinanolone has recorded a MIC of 50-100 microg/mL. The activities are compared with plumbagin (0.78-3.13 microg/mL) and standards streptomycin for bacteria and nystatin for fungi. DISCUSSION: Earlier researchers have established the presence of plumbagin in the roots of P. zeylanica and its antimicrobial activities. The structure elucidation of two more biologically active biogenetic precursors along with their activities in the root extracts has been established for the first time in the present study. CONCLUSION: The root extract of P. zeylanica possesses good antimicrobial activity, which suggests its therapeutic use in the Ayurvedic system of medicine to cure skin diseases.

Continuous production of oxytetracycline in fluidized bed bioreactor by immobilized cells of Streptomyces varsoviensis MTCC-1537: effect of dilution and glucose loading rates.

Oxytetracycline (OT) production using glutaraldehyde cross-linked calcium alginate immobilized cells of Streptomyces varsoviensis in continuous fluidized bed reactor (FBR) was investigated. Initially, batch experiments were carried in stirred tank reactor (STR) and FBR using calcium alginate immobilized cells. Higher OT production of 0.45 gm/L was achieved by FBR when compared with 0.33 g/L of OT in STR. All subsequent studies were carried out in continuous mode of operation in FBR. During 21 days of operation, effect of glucose concentration and different dilution rates were studied. A maximum of 0.75 g/L OT was achieved in the medium having 10 g/L of glucose concentration. The highest OT concentration of 0.92 g/L and the highest yield of OT with respect to biomass at 0.1713 g/g were obtained at the dilution rate of 0.25 day(-1).

Multiple responses optimization and modeling of lipase production by Rhodotorula mucilaginosa MTCC-8737 using response surface methodology.

Response surface methodology was employed to optimize culture medium for production of lipase with Rhodotorula sp. MTCC 8737. In the first step, a Plackett-Burman design was used to evaluate the effects of different inducers qualitatively. Of all the seven inducers tested, soybean oil showed significant influence on the lipase production. Further, response surface studies were conducted to quantitatively optimize by considering linear, interactive, and quadratic effects of test variables. A novel approach was proposed to optimize the lipase production system by optimizing the responses in terms of yield kinetics rather than optimizing the direct responses like lipase titer and biomass growth. The coefficient of determination (R(2)) calculated for Y (P/S) (0.769), Y (P/X) (0.799), and Y (X/S) (0.847) indicated that the statistical model could explain 76.9%, 79.99%, and 84.7% of variability in the response.

Microbial biosynthesis and applications of gentamicin: a critical appraisal.

Gentamicin is an aminoglycoside antibiotic produced by various species of the genus Micromonospora and has received much attention in the recent years as a broad-spectrum antibiotic for treatment of various infections. It exists as a complex of closely related aminoglycoside structures and the clinically significant one is the gentamicin C complex. This review article focuses attention on the present status of knowledge and the main advancements achieved in the last few decades on the subject of gentamicin with regard to its production, biosynthetic pathway, mode of action, and uses. The various nutritional and environmental parameters affecting gentamicin production and the factors affecting the release of bound gentamicin are discussed. Further, strain improvement using UV and/or chemical mutagenesis can be applied to augment the efficiency of the producer strain and a number of case studies are presented. Different detection and quantitative methods for gentamicin estimation and the mode of action of gentamicin are discussed in detail. This antibiotic finds extensive use in combination chemotherapy and as a drug for different delivery agents for treatment of osteomyelitis and other recent applications in gene therapy.

Biomethanation of poultry litter leachate in UASB reactor coupled with ammonia stripper for enhancement of overall performance.

In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26m(3)CH(4)/kg COD reduced), organic loading rate (OLR) (18.5kg COD m(-3)day(-1)) and Hydraulic residence time (HRT) (12h) compared to the UASB reactor without stripper (COD reduction: 92%; methane yield: 0.21m(3)CH(4)/kg COD reduced; OLR: 13.6kg CODm(-3)day(-1); HRT: 16h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9min are found to be optimum parameters for the operation of the stripper.

Effect of aeration and agitation regimes on lipase production by newly isolated Rhodotorula mucilaginosa-MTCC 8737 in stirred tank reactor using molasses as sole production medium.

The influence of media and process parameters (aeration and agitation) on fermentation broth rheology and biomass formation has been studied in 1.5-l stirred tank reactor for lipase production using Rhodotorula mucilaginosa MTCC 8737. Molasses, as sole production medium, is used for lipase production by varying aeration (1, 2, and 3 vvm) and agitation speeds (100, 200, and 300 rpm). Maximum lipase activity of 72 U/ml was obtained during 96 h of fermentation at 2 vvm, 200 rpm, pH 7, and 25 +/- 2 degrees C temperature. Lipase production kinetics with respect to dry cell weight of biomass showed Y (P/S) of 25.71 U/mg, specific product formation of 10.9 U/mg DC, and Y (X/S) 2.35 mg/mg. Maximum lipase activity (MC 2) of 56 U/ml was observed at 1% molasses, and a further increase in the molasses concentration of (%) 1.5 and 2 inhibited the product formation of lipase with 15 and 8.5 U/ml, respectively. The production kinetics of molasses media showed Y (P/X) was 14 U/mg DC, Y (P/S) 16 U/mg, and Y (X/S) 1.14 mg/mg during 96 h of bioreactor operation. The k(L)a values for all batches (MC 1-MC 4) at 96 h of fermentation were 32, 28, 21, and 19/h, and the |oxygen transfer rate were 54.4, 56, 35.7, and 17.29 mg/l h, respectively. Increase in molasses concentration resulted in decreased lipase activity by increase in viscosity of the fermentation broth.

Biological treatment of toxic petroleum spent caustic in fluidized bed bioreactor using immobilized cells of Thiobacillus RAI01.

In the present studies, newly isolated Thiobacillus sp was used for the treatment of synthetic spent sulfide caustic in a laboratory-scale fluidized bed bioreactor. The sulfide oxidation was tested using Ca-alginate immobilized Thiobacillus sp. Initially, response surface methodology was applied for the optimization of four parameters to check the sulfide oxidation efficiency in batch mode. Further, reactor was operated in continuous mode for 51 days at different sulfide loading rates and retention times to test the sulfide oxidation and sulfate and thiosulfate formation. Sulfide conversions in the range of 90-98% were obtained at almost all sulfide loading rates and hydraulic retention times. However, increased loading rates resulted in lower sulfide oxidation capacity. All the experiments were conducted at constant pH of around 6 and temperature of 30 +/- 5 degrees C.

Gentamicin production by Micromonospora echinospora (Me- 22) in stirred tank reactor: effect of various parameters.

Effect of production medium components, initial starch and soyabean meal concentrations, for the enhanced production of gentamicin by Micromonospora echinospora (Me- 22) was studied in a lab scale stirred tank reactor. Also effect of different aeration (0.5, 1, 2, and 4 vvm) and agitation rates (100, 200, 300 and 400 rpm) in a stirred tank reactor was examined. A maximum gentamicin concentration of 2.68 g l(-1) was achieved in the medium having low concentrations of initial starch (7.5 g l(-1)) and high concentrations of initial soyabean meal (4 g l(-1)). Both aeration and agitation significantly affected gentamicin concentration, productivity and biomass formation. The maximum gentamicin concentration of 4.12 g l(-1) and the highest yield of gentamicin on substrate 0.967 g g(-1) were obtained at impeller speed of 200 rpm and aeration rate of 2 vvm. Under optimal culture conditions in STR the production of gentamicin could be increased 3 fold when compared with shake flask.

Evaluation of various parameters of calcium-alginate immobilization method for enhanced alkaline protease production by Bacillus licheniformis NCIM-2042 using statistical methods.

Calcium-alginate immobilization method for the production of alkaline protease by Bacillus licheniformis NCIM-2042 was optimized statistically. Four variables, such as sodium-alginate concentration, calcium chloride concentration, inoculum size and agitation speed were optimized by 2(4) full factorial central composite design and subsequent analysis and model validation by a second-order regression equation. Eleven carbon, 11 organic nitrogen and seven inorganic nitrogen sources were screened by two-level Plackett-Burman design for maximum alkaline protease production by using optimized immobilized conditions. The levels of four variables, such as Na-alginate 2.78%; CaCl(2), 2.15%; inoculum size, 8.10% and agitation, 139 rpm were found to be optimum for maximal production of protease. Glucose, soybean meal and ammonium sulfate were resulted in maximum protease production at 644 U/ml, 720 U/ml, and 806 U/ml when screened for carbon, organic nitrogen and inorganic nitrogen sources, respectively, using optimized immobilization conditions. Repeated fed batch mode of operation, using optimized immobilized conditions, resulted in continuous operation for 12 cycles without disintegration of beads. Cross-sectional scanning electron microscope images have shown the growth pattern of B. licheniformis in Ca-alginate immobilized beads.

Microbial conversion of sulfur dioxide in flue gas to sulfide using bulk drug industry wastewater as an organic source by mixed cultures of sulfate reducing bacteria.

Mixed cultures of sulfate reducing bacteria (SRB) were isolated from anaerobic cultures and enriched with SRB media. Studies on batch and continuous reactors for the removal of SO(2) with bulk drug industry wastewater as an organic source using isolated mixed cultures of SRB revealed that isolation and enrichment methodology adopted in the present study were apt to suppress the undesirable growth of anaerobic bacteria other than SRB. Studies on anaerobic reactors showed that process was sustainable at COD/S ratio of 2.2 and above with optimum sulfur loading rate (SLR) of 5.46kgS/(m(3)day), organic loading rate (OLR) of 12.63kg COD/(m(3)day) and at hydraulic residence time (HRT) of 8h. Free sulfide (FS) concentration in the range of 300-390mgFS/l was found to be inhibitory to mixed cultures of SRB used in the present studies.

Isolation of Thiobacillus sp from aerobic sludge of distillery and dairy effluent treatment plants and its sulfide oxidation activity at different concentrations.

In the present study two strains of Thiobacillus sp were isolated from aerobic sludge of distillery and dairy effluent treatment plant using standard methods of isolation and enrichment. Experiments were conducted using isolated cultures in batch bioreactor with initial sulfide concentration of 75 and 150 mg/l. The effect of initial sulfide concentration on the activity of isolated Thiobacillus sp was studied. Sulfide oxidizing capacity was also determined at different initial sulfide concentrations. The results from the study indicate the possible isolation of Thiobacillus cultures from native source and application in the full-scale reactor

Optimization of nutritional requirements for gentamicin production by Micromonospora echinospora.

Effect of various fermentation media, carbon sources, nitrogen sources, phosphate concentration and culture requirements includes inoculum levels and age were determined on gentamicin production and biomass dry weight production for Micromonospora echinospora, a gentamicin producing strain. Of the substrates tested, starch as a sole carbon source promoted maximal gentamicin production, while maltose promoted maximal growth. Yeast extract as a sole nitrogen source promoted maximal growth, while soyabean meal for gentamicin production. Increasing phosphate concentration enhanced gentamicin production and observed optimum production at 1.2 g/1 (6% v/v) of phosphate having 72 h old inoculum in the medium. Highest gentamicin production was obtained after cultivation with shaking for 120 h in a medium containing starch 0.75% (w/v), soyabean meal 0.5%, K2HPO4 0.12%, CaCO3 0.4%, FeSO4 0.003% and CoCl2 0.0001%. The gentamicin production was 1.2-fold in this medium as compared to basal medium.

Optimization of critical medium components for the maximal production of gentamicin by Micromonospora echinospora ATCC 15838 using response surface methodology.

Optimization of the fermentation medium components for maximum gentamicin production by Micromonospora echinospora ATCC 15838 was carried out. Response surface methodology was applied to optimize the medium constituents. A 2(4) full-factorial central composite design was chosen to explain the combined effects of the four medium constituents, viz. starch, soyabean meal, K2HPO4, and CoCl2 and to design a minimum number of experiments. A second order model was developed and fitted using least square method. The R2 value of the model was 0.9723, which shows that model is best fit for the present studies. The results of analysis of variance and regression of a second order model showed that the linear effects of starch (p < 0.001697) and CoCl2 (p < 7.99E-13), and cross product effects of starch and soyabean meal (p < 0.029876) and soyabean meal and CoCl2 (p < 0.008909) were more significant, suggesting that these were critical variables having the greatest effect on the production of gentamicin in the production medium. The optimized medium consisting of 9 g/L starch, 3 g/L soyabean meal, 0.9 g/L K2HPO4, and 0.01 g/L CoCl2 predicted 850 mg/L of gentamicin which was almost 110% higher than that of the unoptimized medium. The amounts of starch, soyabean meal, and K2HPO4 required were also reduced with RSM.

Antimicrobial activities of bharangin from Premna herbaceae Roxb. and bharangin monoacetate.

The root nodules of Premna herbaceae, which are being used in ayurvedic system of medicine as gantubharangi for curing several ailments, have been studied for antimicrobial activities. The major compound responsible for the biological activity is bharangin, a yellow colored compound extractable with hexane. Bharangin monoacetate prepared by acetylation of bharangin has been investigated along with bharangin for their antimicrobial activity against gram positive and gram negative bacteria and fungi. In general bharangin monoacetate showed more activity with MIC of 3-6 microg/ml when compared with bharangin, which has MIC of 10-25 microg/ml. The enhanced antibacterial activity is attributed to the presence of acetoxyl group in place of hydroxyl group present in the structure of bharangin. The activity is compared with standard gentamycin for bacteria and nystatin for fungi.

Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

Studies were carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater were found to be very high with low biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and startup of the reactor was carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor was studied at different organic loading rates (OLR) and it was found that the optimum OLR was 10 kg COD/m(3)/day. The wastewater under investigation, which had a considerable quantity of SS, was treated anaerobically without any pretreatment. COD and BOD of the reactor outlet wastewater were monitored and at steady state and optimum OLR 60-70% of COD and 80-90% of BOD were removed. The reactor was subjected to organic shock loads at two different OLR and the reaction could withstand the shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS.

Anaerobic treatment of wastewater with high suspended solids from a bulk drug industry using fixed film reactor (AFFR).

Studies are carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater are found to be very high with low Biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and start up of the reactor is carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor is studied at different organic loading rates (OLR) and it is found that the optimum OLR is 10 kg COD/m3/day. The wastewater under investigation, which is having considerable quantity of SS, is treated anaerobically without any pretreatment. The COD and BOD of the reactor outlet wastewater are monitored and reduction at steady state and optimum OLR is observed to be 60-70% of COD and 80-90% of BOD. The reactor is subjected to organic shock loads at two different OLR and it is observed that the reactor could withstand shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS.