Inoculum Volume Research Articles

Biodegradation of Indanthrene Blue RS dye in immobilized continuous upflow packed bed bioreactor using corncob biochar

The current study describes the aerobic biodegradation of Indanthrene Blue RS dye by a microbial consortium immobilized on corn-cob biochar in a continuous up-flow packed bed bioreactor. The adsorption experiments were performed without microbes to monitor the adsorption effects on initial dye decolorization efficiency. The batch experiments were carried out to estimate the process parameters, and the optimal values of pH, temperature, and inoculum volume were identified as 10.0, 30 °C, and 3.0 × 106 CFU mL−1, respectively. During the continuous operation, the effect of flow rate, initial substrate concentration, inlet loading rate of Indanthrene Blue RS on the elimination capacity, and its removal efficiency in the bioreactor was studied. The continuous up-flow packed bed bioreactor was performed at different flow rates (0.25 to 1.25 L h−1) under the optimal parameters. The maximum removal efficiency of 90% was observed, with the loading rate varying between 100 and 300 mg L−1 day−1. The up-flow packed bed bioreactor used for this study was extremely useful in eliminating Indanthrene Blue RS dye using both the biosorption and biodegradation process. Therefore, it is a potential treatment strategy for detoxifying textile wastewater containing anthraquinone-based dyes.

Production of curcumin by engineered Escherichia coli

Curcumin is exclusively isolated from Zingiberaceae plants with a broad spectrum of bioactivities. In the present study, we used the diketide-CoA synthase (DCS) and curcumin synthase (CURS) genes to construct a non-natural fusion gene encoding diketide-CoA synthase::curcumin synthase (DCS::CURS). This fusion protein, together with the acetyl coenzyme A carboxylase (ACC) and the 4-coumarate coenzyme A ligase (4CL), were introduced into Escherichia coli for the production of curcumin from ferulic acid. The process is divided into two stages, the growth stage using LB medium and the fermentation stage using the modified M9 medium. The yield of curcumin reached 386.8 mg/L by optimizing the induction of protein expression in the growth stage, and optimizing the inoculum volume, medium composition and fermentation time in the fermentation stage, as well as the addition of macroporous resin AB-8 into the second medium to attenuate the toxicity of the end product. The exploitation of the non-natural fusion protein DCS::CURS for the production of curcumin provides a new alternative to further promoting the production of curcumin and the related analogues.

Optimization of Moist and Oven-Dried Bacterial Cellulose Production for Functional Properties.

Bacterial cellulose (BC) is a natural polymer with properties suitable for tissue engineering and possible applications in scaffold production. However, current procedures have limitations in obtaining BC pellicles with the desired structural, physical, and mechanical properties. Thus, this study analyzed the optimal culture conditions of BC membranes and two types of processing: draining and oven-drying. The aim was to obtain BC membranes with properties suitable for a wound dressing material. Two studies were carried out. In the preliminary study, the medium (100 mL) was inoculated with varying volumes (1, 2, 3, 4, and 5 mL) and incubated statically for different periods (3, 6, 9, 12, and 18 days), using a full factorial experimental design. Thickness, uniformity, weight, and yield were evaluated. In the optimization study, a Box–Behnken design was used. Two independent variables were used: inoculum volume (X1: 1, 3, and 5 mL) and fermentation period (X2: 6, 12, and 18 d) to determine the target response variables: thickness, swelling ratio, drug release, fiber diameter, tensile strength, and Young’s modulus for both dry and moist BC membranes. The mathematical modelling of the effect of the two independent variables was performed by response surface methodology (RSM). The obtained models were validated with new experimental values and confirmed for all tested properties, except Young’s modulus of oven-dried BC. Thus, the optimal properties in terms of a scaffold material of the moist BC were obtained with an inoculum volume of 5% (v/v) and 16 d of fermentation. While, for the oven-dried membranes, optimal properties were obtained with a 4% (v/v) and 14 d of fermentation.

Eco-friendly bioprocess using agar plug immobilized Penicillium crustosum PWWS-6 biomass for treatment of wastewater contaminated with toxic Congo red dye for use in agriculture

Recycling and valorization of noxious dye contaminated industrial wastewater minimize prevailing agricultural water dearth. In this context, the current manuscript investigates and fabricates a rapid, ecofriendly, and cost effective treatment system using a potent dye degrading microbial agent. An agar plug immobilized Penicillium crustosum PWWS-6, a filamentous fungus isolated from veterinary clinical waste dump, for the first time reported to decolorize (81.86 ± 0.03 %) hazardous diazo dye, (Congo red, 100 ppm) in 24 h. Lignin peroxidase, azo reductase, veratryl alcohol oxidase, and NADH-DCIP reductase enzymes were induced significantly during mycoremediation bioprocess which is affected by incubation time, temperature, pH, inoculum volume, and dye concentration of aqueous medium. The one-factor-at-a-time (OFAT) and response surface methodology (RSM) were adopted to optimize these cultural parameters and generated optimized conditions (incubation time, 16 h; temperature, 27 °C; and inoculum volume, 6 fungal discs), for maximum degradation (99.85 %) of 100 ppm CR at pH 7.0. Further, using OFAT approach, P. crustosum also showed 72.14 % degradation of CR at much higher concentration of 1000 ppm in 72 h. UV–vis spectra verified complete disappearance of dye from colored broth. Fourier Transform Infrared (FTIR) spectroscopy along with Field Emission Scanning Electron Microscopy (FESEM) subsequently confirmed (–N=N–) bond destabilization following degradation. Furthermore, the non-toxic degraded metabolites showed improved percent germination, radical and plumule length of Cicer arietinum and Hordeum vulgare seeds compared with untreated CR contaminated wastewater.

Sustained energy production from wastewater in microbial fuel cell: effect of inoculum sources, electrode spacing and working volume.

The present study was aimed at producing enhanced and sustained bioelectricity from distillery wastewater in a doublechamber microbial fuel cell (MFC) by changing inter-electrode distance, inoculum and reactor volume. Using double chamber MFC with 1 L working volume, when the distance between the electrodes was kept shorter (1cm), it generated power density of 1.74W/m3, which was 42.5% higher than that of MFC with electrode spacing of 10cm (1W/m3). Using inoculum from different sources viz. garden soil (MFC-GS), wetland sediment (MFC-WS) and sludge from wastewater treatment plant (MFC-S), the highest open circuit voltage (OCV) of 0.84V and power density of 2.74W/m3 were produced by MFC-WS, which also showed sustained electricity production (1.68W/m3) from the wastewater during a 10-day experiment. Relatively lower power density was generated from MFC-S (1.42W/m3), while that from MFC-GS was the lowest (0.94W/m3). Bioelectricity generation and overall performance were then assessed using a smaller reactor size. Smaller working volume of MFC (250ml) favoured greater production of power density (3.2W/m3) than that with 1 L working volume (2.96W/m3) with electrode distance of 1cm. The present study was novel in selecting a suitable mixed-microbial inoculum out of the diverse sources screened and reducing resistance by sharply narrowing down inter-electrode distance and reactor volume, which led to significantly enhanced and sustained electricity generation fromdoublechamber MFC.

Optimization and Degradation Studies on Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) with Selected Indigenous Microbes under Aerobic Conditions

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) a nitramine explosive, which has contaminated various military sites during its use, storage and manufacturing worldwide. As RDX is a recalcitrant, less soluble and toxic to human beings and other organisms, it is essential to remediate the contaminated sites. In the current investigation, authors have explored the potential of two indigenous microbes i.e., Bacillus toyonensis (isolate No. WS4-TSB-3, MTCC No. 12857) and Paenibacillus dendritiformis (isolate No. S10-TSA-3, MTCC No. 12859) isolated from an explosive manufacturing facility in north India, for the degradation of RDX in aqueous medium. Furthermore, RDX degradation has been optimized using response surface methodology (RSM) in a 15 days experiment at concentration of 20, 40, and 60 mg/L. It was found that various factors such as initial concentration of RDX, inoculum volume (2, 4 and 6%) and time (5, 10 and 15 days) had impact on transformation and degradation of contaminant. Samples were analyzed using high performance liquid chromatography (HPLC) and intermediate products were identified using LC-MS/MS. Maximum RDX removal of 81.6 ± 1.3 and 84.7 ± 0.9% for Bacillus toyonensis (isolate No. WS4-TSB-3) and Paenibacillus dendritiformis (isolate No. S10-TSA-3), respectively, was observed on 15th day at 40 mg/L initial concentration. During the degradation Hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), Hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), 4-Nitro-2,4-diazabutanal, Bis(hydroxymethyl)nitramine and nitrite were identified as intermediate products. The findings of the investigation suggest that both the microbes have the potential to degrade RDX in the aqueous medium and can be used for up-scaling the degradation of RDX on explosive contaminated sites.

Bioethanol Production from an Underutilized Plant, Calabash (Crescentia Cujete) Using Co-Culture of Saccharomyces Cerevisiae and Cronobacter Malonaticus

Response surface methodology (RSM) model was used to optimize ethanol production from calabash (Crescentia cujete) pulp juice using co-culture of Saccharomyces cerevisiae and Cronobacter malonaticus. The calabash pulp was squeezed with muslin cloth, and vacuum filtered to clear solution before use. The clear juice was tested for reducing sugars using the Dinitrosalicylic acid (DNS) method. Twenty three runs (23), including 3 controls, of the fermentation were conducted at varying temperatures, pH, and volumes of inoculum. The process parameters (input variables): volumes of inoculum, temperature, and pH were subjected to response surface model, using the Central composite design (CCD). Fermentation was done in conical flasks covered with cotton wool and foil in a stationary incubator for four days (96 hours). Active co-culture of Saccharomyces cerevisiae and Cronobacter malonaticus was used, with inoculum developed using Marcfaland’s method. Samples were collected every 24 hours, centrifuged, filtered and analyzed for measurement of the output variables: reducing sugar, cell density and ethanol concentration. The concentration of reducing sugars from Calabash pulp was 3.2 mg/ml. Results obtained also revealed that the fermentation can take place on a wide range of temperature; 29-31.60C . The optimal pH range for performance of the co-culture for the fermentation process was pH range 7.9- 8.0. The optimum volume of inoculum was 5.5%v/v (ie 5.5 ml in 94.5ml juice). The optimized process using the RSM model gave 6.97% v/v bioethanol at 29oC and pH 7.9. The bioethanol yield from Calabash substrate is reasonable with co-culture considering the concentration of reducing sugars obtained from the juice and the duration of the fermentation.

Bioleaching of vanadium by Acidithiobacillus ferrooxidans from vanadium-bearing resources: Performance and mechanisms

Bioleaching is promising to meet the demand of strategic vanadium both economically and environmentally. Whereas the combination of bioleaching with traditional techniques is of great interest, little is known on bioleaching of vanadium from abundant vanadium-bearing resources utilized/produced in existing processes. This study investigated the bioleaching of vanadium from vanadium-titanium magnetite, steel slag, and clinker, which are common raw mineral and intermediates used in conventional vanadium extraction process. Clinker had greater leachability by Acidithiobacillus ferrooxidans, compared to vanadium-titanium magnetite and steel slag. Pulp density, inoculum volume, initial pH and initial Fe2+ concentration had influencing effects on this bioleaching process. Under optimal condition with 3% pulp density, 10% inoculum volume, initial pH at 1.8, and 3 g/L initial Fe2+ concentration, the bioleaching of clinker achieved the maximum vanadium leaching efficiency of 59.0%. Both X-ray fluorescence and energy dispersive spectroscopy analysis confirmed the reduction of vanadium content in the solid residues after leaching. The results of Community Bureau of Reference sequential extraction suggested that vanadium in acid-soluble and oxidizable phase was more easily leachable. This study is helpful to develop sustainable and practical techniques for vanadium extraction from abundant raw materials and step forward in combining bioleaching with traditional process.

Biodegradation of phenol by a halotolerant versatile yeast Candida tropicalis SDP-1 in wastewater and soil under high salinity conditions

In this study, a novel halotolerant phenol-degrading yeast strain, SDP-1, was isolated from a coastal soil in Jiangsu, China, and identified as Candida tropicalis by morphology and rRNA internal transcribed space region sequence analysis. Strain SDP-1 can efficiently remove phenol at wide ranges of pH (3.0–9.0), temperature (20–40 °C), and NaCl (0–5%, w/v), as well as the tolerance of Mn2+, Zn2+ and Cr3+ in aquatic phase. It also utilized multiple phenol derivatives and aromatic hydrocarbons as sole carbon source and energy for growth. Free cells of SDP-1 were able to degrade the maximum phenol concentration of 1800 mg/L within 56 h under the optimum culture conditions of 10% inoculum volume, pH 8.0, 35 °C and 200 rpm agitation speed. Meanwhile, SDP-1 was immobilized on sodium alginate, and the capability of efficiently phenol degradation of free cells and immobilized SDP-1 were evaluated. Shortened degradation time and long-term utilization and recycling for immobilized SDP-1 was achieved compared to free cells. The 1200 mg/L of phenol under 5% NaCl stress could be completely degraded within 40 h by immobilized cells. In actual industrial coking wastewater, immobilized cells were able to completely remove 383 mg/L phenol within 20 h, and the corresponding chemical oxygen demand (COD) value was decreased by 50.38%. Besides, in phenol-contained salinity soil (3% NaCl), 100% of phenol (500 and 1000 mg/kg) removal efficiency was achieved by immobilized SDP-1 within 12 and 26 days, respectively. Our study suggested that versatile yeast Candida tropicalis SDP-1 could be potentially used for enhanced treatment of phenol-contaminated wastewater and soil under hypersaline or no-salt environmental conditions.

Bioremediation of lindane contaminated soil: Exploring the potential of actinobacterial strains

Lindane, an organochlorine pesticide, causes detrimental impacts on the environment and human health owing to its high toxicity, low degradation, and bioaccumulation. Its toxic nature can be overcome by biological and eco-friendly approaches involving its degradation and detoxification. The biodegradation of lindane was assessed using actinobacterial species Thermobifida cellulosilytica TB100 (T. cellulosilytica), Thermobifida halotolerans DSM 44931 (T. halotolerans) and Streptomyces coelicolor A3 (S. coelicolor). The degradation conditions of Lindane such as pH, temperature, inoculum volume, glucose concentration and number of days were optimized under broth conditions. Lindane degradation at different concentrations was studied in soil using reverse phase-high performance liquid chromatography over a 30 day period. A bioassay test was performed on seeds of Lactuca sativa (Lettuce) to assess the success of bioremediated soil. Maximum lindane degradation in soil was observed using T. cellulosilytica sp. The degradation trend for different concentrations of lindane using T. halotolerans in sterilized soil was 55 mg kg−1 (82%) ˃ 155 mg kg−1 (75%) ˃ 255 mg kg−1 (70%) after an incubation period of 30 days. Lindane degradation in soil followed the first order reaction kinetics. Phytotoxicity test on seeds of Lactuca sativa showed considerably good vigor index values for the bioremediated sterilized and non-sterilized soil by T. cellulosilytica, T. halotolerans and S. coelicolor in comparison to the contaminated soil without bacteria. This confirms that these actinobacterial species can be implemented in bioaugmentation of contaminated sites to efficiently remediate high lindane concentrations.

Outdoor scale‐up of Leptolyngbya sp.: Effect of light intensity and inoculum volume on photoinhibition and ‐oxidation

The effect of light intensity and inoculum volume on the occurrence of photooxidation for Leptolyngbya sp. QUCCCM 56 was investigated, to facilitate the transition from small‐scale laboratory experiments to large‐scale outdoor cultivation. Indoor, the strain was capable of growing at light intensities of up to 5600 µmol photons/m2/s, at inoculation densities as low as 0.1 g/L (10% inoculation volume vol/vol). Levels of chlorophyll and phycocyanin showed a significant decrease within the first 24 h, indicating some level of photooxidation, however, both were able to recover within 72 h. When cultivated under outdoor conditions in Qatar during summer, with average peak light intensities 1981 ± 41 μmol photons/m2/s, the strain had difficulties growing. The culture recovered after an initial adaptation period, and clear morphological differences were observed, such as an increase in trichome length, as well as coiling of multiple trichomes in tightly packed strands. It was hypothesized that the morphological changes were induced by UV‐radiation as an adaptation mechanism for increased self‐shading. Furthermore, the presence of contaminating ciliates could have also affected the outdoor culture. Both UV and contaminants are generally not simulated under laboratory environments, causing a mismatch between indoor optimizations and outdoor realizations.

Tolerance of Yarrowia lipolytica to inhibitors commonly found in lignocellulosic hydrolysates

BackgroundLignocellulosic material is a suitable renewable carbon and energy source for microbial cell factories, such as Yarrowia lipolytica. To be accessible for microorganisms, the constituent sugars need to be released in a hydrolysis step, which as a side effect leads to the formation of various inhibitory compounds. However, the effects of these inhibitory compounds on the growth of Y. lipolytica have not been thoroughly investigated.ResultsHere we show the individual and combined effect of six inhibitors from three major inhibitor groups on the growth of Y. lipolytica. We engineered a xylose consuming strain by overexpressing the three native genes XR, XDH, and XK and found that the inhibitor tolerance of Y. lipolytica is similar in glucose and in xylose. Aromatic compounds could be tolerated at high concentrations, while furfural linearly increased the lag phase of the cultivation, and hydroxymethylfurfural only inhibited growth partially. The furfural induced increase in lag phase can be overcome by an increased volume of inoculum. Formic acid only affected growth at concentrations above 25 mM. In a synthetic hydrolysate, formic acid, furfural, and coniferyl aldehyde were identified as the major growth inhibitors.ConclusionWe showed the individual and combined effect of inhibitors found in hydrolysate on the growth of Y. lipolytica. Our study improves understanding of the growth limiting inhibitors found in hydrolysate and enables a more targeted engineering approach to increase the inhibitor tolerance of Y. lipolytica. This will help to improve the usage of Y. lipolytica as a sustainable microbial cell factory.

Response surface methodology and optimization of the processes for bioethanol production from Calabash (Crescentia cujete) Using Cronobacter malonaticus

Aim: Response surface methodology (RSM) model was applied to optimize ethanol production from Calabash (Crescentia cujete) pulp juice using Cronobacter malonaticus. Study Design: The Calabash pulp was squeezed with muslin cloth, and vacuum filtered to clear solution before use. The clear juice was tested for reducing sugars using the Dinitrosalicylic acid (DNS) method. Twenty three (23) runs, including 3 controls, of the fermentation was conducted at varying temperatures, pH, and volumes of inoculum. The process parameters (input variables): volumes of inoculum, temperature, and pH were subjected to response surface model, using the Central Composite Design (CCD). Place and Duration of Study: This study was carried out in the Environmental Microbiology Laboratory, University of Port Harcourt for six months. Methodology: Fermentation was done in conical flasks covered with cotton wool and foil in a stationary incubator for four days (96 hours). Active stock culture of Cronobacter malonaticus was used, with inoculum developed using Marcfaland’s method. Samples were collected every 24 hours, centrifuged, filtered and analyzed for measurement of the output variables: Reducing sugar, cell density and ethanol concentration. Results: The concentration of reducing sugars from Calabash pulp was 3.2 mg/ml. Results obtained also revealed that the fermentation can take place on a wide range of temperature 28-32°C. The optimal pH range for performance of C.malonaticus for the fermentation process was pH 5.95-6.5. The optimum volume of inoculum was 10%v/v (i.e. 10 ml in 90 ml juice). The optimized process using the RSM model gave 5.08% v/v bioethanol, being the highest achieved at pH6.08 and 28oC . Conclusion: The bioethanol yield from Calabash substrate is reasonable considering that the bacterium used is not known for ethanol production. Also the concentration of reducing sugars in the substrate and the duration of fermentation could be responsible for the yield.

Optimization and comparison of \u213d-aminobutyric acid (GABA) production by LAB in soymilk using RSM and ANN models

Backgroundℽ-Aminobutyric acid (GABA) is a non-proteinaceous amino acid. In the mammalian nervous system, GABA functions as an inhibitory neurotransmitter. The present study focused on screening and optimization of ℽ-aminobutyric acid (GABA) yield by lactic acid bacteria by using soymilk as basal media. Lactobacillus fermentum (Lb. fermentum) was isolated from sourdough. The qualitative confirmation of GABA production by Lb. fermentum was observed by detecting colored spots on thin layer chromatography plate (TLC) and comparing it with standard GABA spot. The GABA from bacteria is confirmed by its molecular mass using mass spectrophotometry analysis (MS analysis). Single variable experiments were conducted for various physical and nutritional parameters, and determined the GABA content produced from Lb. fermentum, viable bacterial count, and pH of the fermented soymilk medium. Experimental data were authenticated by using response surface method (RSM) and artificial neural network (ANN) model.ResultsThe results demonstrated that through single variable experiments, the yield of GABA and the viable bacterial cells increased in soymilk containing one percent of glucose, monosodium glutamate (MSG), and inoculum volume incubated at 37 °C, 48 h at pH 5. According to RSM results, the interaction of the highest concentration of MSG (1.5%) and mid glucose concentration (1.156%) yielded maximum GABA (5.54 g/L). The experimental data were in good agreement with two optimization models. The RSM models showed less error percentage than that of the ANN model.ConclusionThis study indicates that soymilk is the best basal substrate for GABA production and growth of Lb. fermentum compared to synthetic media. Lb. fermentum can be explored further by food and pharmaceutical industries for the development of functional foods and therapeutic purposes.

Bioremediation of synthetic textile dyes using live yeast Pichia pastoris

Abstract A comparative study of the accumulation of Reactive Red 11 (RR11) and Acid Green 1 (AG1) dyes using live yeast culture Pichia pastoris (P. pastoris) was investigated. The changes in inoculum volume, pH, initial dye concentration and incubation temperature were studied. The maximum percentage of color removal efficiency, dye uptake capacity and bioaccumulation concentrations were found at pH 2. The maximum dried biomass concentration was found at pH 3. When the dye concentration increased, the percentage of color removal, specific growth rate and dried biomass concentrations decreased. However, the dye uptake capacity increased with an increase in the initial dye concentration. At an ambient temperature of 30 °C, the uptake efficiency for both the dyes was optimal The yeast biomass was characterized using scanning electron microscopic (SEM) image and fourier transform infrared (FTIR) spectral analysis. In this study, P. pastoris accumulated both dyes and was found to be more suitable for AG1 dye than RR11 dye.

Metallic composites based on Ag, Cu, Au and Ag-Cu nanoparticles with distinctive bactericidal effect on varied species

Because the spread of antimicrobial resistance is impacting current health, environmental, and technological developments, the synthesis of novel and efficient antibacterial agents is required. In this work, nanoparticles of Ag, Cu, Au and Ag-Cu were supported on TiO2 Degussa P25 by the deposition-precipitation with urea method (DPU). The antibacterial performance of these materials, well known as catalysts of reactions of environmental interest, was evaluated against four different bacterial species; which are related to airborne (S. pneumoniae and P. aeruginosa) and waterborne (E. coli and S. aureus) infections. To know the minimum concentration of each composite in relation to the viability of the above mentioned microorganisms, the minimum bactericidal concentration (MBC) technique was used. The model of this work standardized an inoculum volume of bacteria of around 104 bacterial cells per milliliter, which is the average bacterial load of microorganisms found in contaminated environments, the bacterial growth was followed for 24 h. The results showed that all the bacterial species were sensitive to the majority of composites, except to the Au-based composite, because most bacterial species were resistant to it. The highest bactericidal efficiency was obtained with the bimetallic composite Ag-Cu/TiO2, which showed MBC values of 62.5 mM for both the S. aureus and P. aeruginosa species, and 31.15 and 15.6 mM for the E. coli and S. pneumonia species, respectively. The bactericidal effectiveness of all materials was ranked in the following order Ag/Cu > Ag > Cu > Au.

Cultivation characteristics and yield of Sparassis crispa according to medium pH, medium moisture content, and inoculum volume of liquid spawn

Cultivation characteristics and yield of Sparassis crispa according to medium pH, medium moisture content, and inoculum volume of liquid spawn

Miniaturized Microbiological Method to Determine the Potency of Rifaximin in Tablets.

Rifaximin, a semi-synthetic antimicrobial, does not present microbiological method described in official compendia, and there is a lack of literature on this topic. The quality control of antimicrobials is extremely important to evaluate the real potency of pharmaceutical products. A miniaturized turbidimetric method for determining the potency of rifaximin in tablets was developed and validated by turbidimetry, according to the international guidelines. Escherichia coli ATCC 10536 IAL 2393, brain heart infusion (BHI) broth, inoculum at 8%, rifaximin in purified water with 20% ethanol at 5, 10, and 20 μg/mL and 530 nm were used. The method was considered selective for rifaximin, as the adjuvants did not show activity; linear with correlation coefficients 0.9998 for standard and 0.9999 for sample; accurate with 99.73% recovery; precise with RSD less than 3%; and robust in the face of small variations in (i) rifaximin volume, (ii) proportion of ethanol, (iii) inoculum volume. The method is considered adequate and safe to evaluate the potency of rifaximin in tablets, contemplating speed, low cost, low waste generation, and ease of operation. This work usescurrent, sustainable, and green analytical chemistry and can be used in the routine analyses of rifaximin by laboratories and the pharmaceutical industry around the world.

Grape pomace as a promising source for gellan gum production

The aim of the present study was to determine the potential use of grape pomace, local agricultural waste, as a sole carbon source in the production of gellan gum. For this purpose, optimization of fermentation conditions of Sphingomonas paucimobilis (ATCC 31461) to produce gellan gum with the maximum yield was studied. This study clearly confirmed that gellan yield depended on carbon source concentration, bacterial inoculum volume and mixing rate. Maximum yield was found as 12.08 g/L at 5% carbon ratio, 4% inoculum volume and mixing rate at 300 rpm. The conversion ratio of waste product into gellan gum was identified as 0.24 gellan gum/grape pomace (g/g). Commercial gellan gum samples had glucose:rhamnose:glucuronic acid ratio as around 2.6:1.15:1, while biosynthesized gellan gum had 2.6:0.5:1 which indicated the effect of carbon source on chemical composition of gelllan gum. The molecular weights of biosynthesized and commercial gellan were determined as 6.88 × 105, 1 × 106, respectively. FTIR and 1H NMR spectral analysis were applied for the purpose of clarifying structures of polymers. Regarding the rheological properties, Herschel–Bulkley model better described the flow behavior of the gum solutions. The commercial gellan gum showed higher viscosity than the biosynthesized gellan. Rheological properties of polymer were affected by changes in the acyl substitution. The biosynthesized gellan from grape pomace showed better stability against temperature changes than commercial gellan gum.

Production of Chitinase from Chromobacterium violaceum Using Agro Industrial Residues under Solid State Fermentation

Chitinases have huge potential applications and biological value in industries, they are used in generating single cell proteins, sweeteners, insecticides, antifungal drugs, anti-cancer agents, biopesticides, food processing agents, degrading agents for sea waste etc. Chitinases are used for the conversion of chitin a polysaccharide into monomers. Chitin is produced enormously in the biosphere annually from fungal cell walls, exoskeletons of insects and crustaceans. Chitinases producing microorganisms Bacillus licheniformis, Chromobacterium violaceum, Rhizobium radiobacter, Streptomyces griseous were obtained from microbial type culture collection. Solid state fermentation was done on Naturally available substrates like Fish scale waste, Prawn shell waste, Wheat bran, Potato peel, Grape leaf to check the enhanced production of Chitinase. Prawn shell waste was found to be the best natural substrate for high activity of Chitinase (464.98 U/g). The overall maximum yield of Chitinase, Chtinolytic activity (531.66 U/gds) was achieved with the optimized process parameters of incubation time(60th h), temperature(34°), inoculum age(3rd d), inoculums volume(20 % v/w), pH(7.0) moisture content 60 % v/w), 1.5 % w/w starch as Carbon source supplement and 1 % w/w urea as Nitrogen source supplement. Both physico-chemical and nutritional parameters had played a significant role in the production of the Chitinase enzyme.