Annapurna Jetty

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.

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.

Neomycin production with free and immobilized cells of Streptomyces marinensis in an airlift reactor

Abstract Neomycin production by free and alginate immobilized Streptomyces marinensis cells was investigated in an airlift reactor. Neomycin production was increased two and a half times with immobilized cells. A marginal decrease in neomycin production was noticed with reduced supplementation of carbon source (up to one-fourth concentration). Immobilized S. marinensis particles showed a half-life of 20 days during continuous fermentation in an airlift reactor.

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.

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 24full-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.

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 µg/mL. Results: 1-Epineo-isoshinanolone is more active with a MIC of 12.5-25 µg/mL whereas neoisoshinanolone has recorded a MIC of 50-100 µg/mL. The activities are compared with plumbagin (0.78-3.13 µg/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.

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 (R2) calculated for YP/S (0.769), YP/X (0.799), and YX/S (0.847) indicated that the statistical model could explain 76.9%, 79.99%, and 84.7% of variability in the response.

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. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Hydrogen Sulfide Removal in Biofilter: Evaluation of a New filter Material by Immobilization of Thiobacillus sp.

Different agricultural residue was evaluated as a biofilter material for the removal of Hydrogen sulfide (H2S) using Thiobacillus sp. A Combination of four different agricultural residues, viz., sugarcane bagasse, coconut coir pith, rice husk and saw dust were evaluated as biofilter material. From results, it was observed that filter material having composition of 2:4:2:2, 4:4:2:2 and 4:2:2:4 has resulted in retaining 70% moisture content at the end of 10 days. The biofilter was operated for 128 days in three phases by varying inlet H2S concentration from 321 to 2020 ppmv. Biofilter exhibited 100% removal efficiency (RE) at an inlet concentration of 570 ppmv, 99% RE at an inlet concentration of 1416 ppmv and 66% RE at a maximum inlet concentration of 2020 ppmv. The filter performance in terms of RE, dropped to 48% when the air was not humidified before sending to the filter, which has direct relation with the MC of the filter material. The RE recovered to 66% with recovery of moisture content (MC) to 57% upon subsequent re-introduction of the humidifier in to the circuit. The pH has dropped from 7.8 to 4.8 during the course of operation of the filter. H2S was effectively removed under different operating conditions using mixed agricultural residue as filter material. However humidification was most essential to maintain the required moisture content in the biofilter. SEM analysis has shown the good growth of Thiobacillus sp. in the filter bed and hence the new material proved to be good support for the immobilization of Thiobacillus sp.