Unoptimized Conditions Research Articles

Central composite design for optimizing istamycin production by Streptomyces tenjimariensis.

Istamycins (ISMs) are 2-deoxyfortamine-containing aminoglycoside antibiotics (AGAs) produced by Streptomyces tenjimariensis ATCC 31603 with broad-spectrum bactericidal activities against most of the clinically relevant pathogens. Therefore, this study aimed to statistically optimize the environmental conditions affecting ISMs production using the central composite design (CCD). Both the effect of culture media composition and incubation time and agitation rate were studied as one factor at the time (OFAT). The results showed that both the aminoglycoside production medium and the protoplast regeneration medium gave the highest specific productivity. Results also showed that 6days incubation time and 200rpm agitation were optimum for their production. A CCD quadratic model of 17 runs was employed to test three key variables: initial pH, incubation temperature, and concentration of calcium carbonate. A significant statistical model was obtained including, an initial pH of 6.38, incubation temperature of 30 ˚C, and 5.3% CaCO3 concentration. This model was verified experimentally in the lab and resulted in a 31-fold increase as compared to the unoptimized conditions and a threefold increase to that generated by using the optimized culture media. To our knowledge, this is the first report about studying environmental conditions affecting ISM production as OFAT and through CCD design of the response surface methodology (RSM) employed for statistical optimization. In conclusion, the CCD design is an effective tool for optimizing ISMs at the shake flask level. However, the optimized conditions generated using the CCD model in this study should be scaled up in a fermenter for industrial production of ISMs by S. tenjimariensis ATCC 31603 considering the studied environmental conditions that significantly influence the production proces.

Enhancing Microalgal Biomass and Chemical Composition for Sustainable Wastewater Treatment

The research explores enhancing microalgal biomass production and its chemical composition for sustainable wastewater treatment. By using the Central Composite Design (CCD) methodology, nutrient concentrations and microbial components in the growth medium were optimized. Adjustments to light exposure, particularly with red and blue frequencies, significantly improved biomass yield, carbon sequestration, and protein content. Optimal light intensity further enhanced these parameters. A process incorporating on-demand CO2 supply and controlled pH levels showed potential for increasing biomass concentrations and nutrient utilization efficiency. Results demonstrated a 28% increase in biomass fixation and a 27% increase in biomass production compared to unoptimized conditions. The study emphasizes the effectiveness of integrated approaches in boosting biomass production and optimizing wastewater treatment, offering promising avenues for sustainable bio-based solutions

Optimization, gene cloning, expression, and molecular docking insights for enhanced cellulase enzyme production by Bacillus amyloliquefaciens strain elh1

BackgroundIn this study, we isolated a cellulase-producing bacterium, Bacillus amyloliquefaciens strain elh, from rice peel. We employed two optimization methods to enhance the yield of cellulase. Firstly, we utilized a one-variable-at-a-time (OVAT) approach to evaluate the impact of individual physical and chemical parameters. Subsequently, we employed response surface methodology (RSM) to investigate the interactions among these factors. We heterologously expressed the cellulase encoding gene using a cloning vectorin E. coli DH5α. Moreover, we conducted in silico molecular docking analysis to analyze the interaction between cellulase and carboxymethyl cellulose as a substrate.ResultsThe bacterial isolate eh1 exhibited an initial cellulase activity of 0.141 ± 0.077 U/ml when cultured in a specific medium, namely Basic Liquid Media (BLM), with rice peel as a substrate. This strain was identified as Bacillus amyloliquefaciens strain elh1 through 16S rRNA sequencing, assigned the accession number OR920278 in GenBank. The optimal incubation time was found to be 72 h of fermentation. Urea was identified as the most suitable nitrogen source, and dextrose as the optimal sugar, resulting in a production increase to 5.04 ± 0.120 U/ml. The peak activity of cellulase reached 14.04 ± 0.42 U/ml utilizing statistical optimization using Response Surface Methodology (RSM). This process comprised an initial screening utilizing the Plackett–Burman design and further refinement employing the BOX -Behnken Design. The gene responsible for cellulase production, egl, was effectively cloned and expressed in E. coli DH5α. The transformed cells exhibited a cellulase activity of 22.3 ± 0.24 U/ml. The egl gene sequence was deposited in GenBank with the accession number PP194445. In silico molecular docking revealed that the two hydroxyl groups of carboxymethyl cellulose bind to the residues of Glu169 inside the binding pocket of the CMCase. This interaction forms two hydrogen bonds, with an affinity score of −5.71.ConclusionsOptimization of cultural conditions significantly enhances the yield of cellulase enzyme when compared to unoptimized culturing conditions. Additionally, heterologous expression of egl gene showed that the recombinant form of the cellulase is active and that a valid expression system can contribute to a better yield of the enzyme.

Antimicrobial Effect of Response Surface Optimized Pyocyanin Produced by Pseudomonas aeruginosa

Pseudomonas aeruginosa is notable for its natural bluish-green pigment production, known as pyocyanin. Researchers have credited pyocyanin as an antimicrobial agent, in addition to its other biomedical applications. This study focused on isolating Pseudomonas aeruginosa from the local environment with the ability to synthesize pyocyanin and optimize its cultural conditions for improved yield. A total of thirty-one experimental combinations of process variables using the Central Composite Design (CCD) of Response Surface Methodology (RSM) was ran to find the best conditions for the organism to make pigments. Of the fermentation media evaluated, nutrient broth supplemented with maltose was the best fermentation medium for the organism’s pyocyanin production. A regression model described the interaction between the test variables and the pyocyanin yield with an R2 value of 87.52%, indicating that the model had a satisfactory fitness level. The determined optimal conditions include a maltose concentration of 18 g/L, a pH of 6.8, an inoculum size of 2.3 mL, and an agitation speed of 120 rpm. The optimized condition resulted in a 4.12-fold increase in pyocyanin yield compared to an unoptimized condition. Pyocyanin exhibits high antimicrobial activity compared to the conventional antibiotics assessed against E. coli and Candida albicans. Our study’s findings suggest that statistical models can improve pyocyanin synthesis by Pseudomonas aeruginosa. Furthermore, this pigment has the potential to replace conventional antibiotics in the treatment of microbial infections

Enhancing bio-isoprene production in Escherichia coli through a combinatorial optimization approach

This study proposed a two-step process optimization for enhanced cumulative isoprene production. This involves establishing an isoprene biosynthetic pathway in Escherichia coli BL21 DE-3 via up-regulation of native deoxy xylulose 5-phosphate (DXP) synthase (EcDXS), isopentenyl pyrophosphate isomerase (EcIPPI/EcIDI) and introducing isoprene synthase (PmIspS) from kudzu (Pueraria montana), followed by the process conditions (incubation temperature, time, and inducer concentration) optimization using the Box-Behnken design (BBD) approach. BBD showed the maximum cumulative isoprene production (160.15 mg L-1), productivity (11.18 mg L-1 h-1), and yield (7.69 mg gdcw-1) at the optimized process conditions (incubation temperature 27.32 ºC, incubation time 14.25 h, and inducer concentration 0.453 mM). The transgenic E. coli isoprene production, -productivity, and -yield were 1.52-, 1.46-, and 1.24-fold higher than the unoptimized condition (incubation temperature 30 ºC, incubation time 16 h, and inducer concentration 0.10 mM). This work demonstrates that fine tuning of MEP pathway in addition with process conditions optimization is an efficient strategy for improving isoprene production from engineered E. coli.

Machine learning approach for the effectual production of a novel esterase and its application in bioremediation of dairy effluent

The present work intends to maximize the production of an industrially important novel esterase from Trichoderma harzianum using both machine learning and statistical approaches and its application in the bioremediation of dairy effluent. Significant medium compounds, such as almond oil, casein, NaH2PO4, and trace elements, were screened from a pool of carbon, nitrogen, oil and surfactant sources along with other micronutrients using a first order statistical design. The optimum value of screened parameters was found using response surface methodology that resulted in the maximum esterase production of 2985.31 U/L. Artificial neural network trained with the experimental response of RSM experiments coupled with genetic algorithm optimization technique has resulted in the maximum esterase production of 3256.73 U/L, which is 150-folds higher as compared to the unoptimized condition and also found to be the higher than the outcome of statistical optimization. Dairy effluent was used for the production of esterase as well as for its bioremediation. At 50% load, the maximum reduction in chemical oxygen demand and the production of esterase were observed to be 46.84% and 34.12 U/L, respectively. The COD reduction of diary effluent was modelled using Michaelis-Menten kinetics and the kinetic parameters, half saturation constant (Km) and maximum reaction rate (rmax) value were evaluated as 286.88 mg/L and 26.04 mg/L/d, respectively.

Multiparameter optimization of microbial fuel cell outputs using linear sweep voltammetry and microfluidics

A microbial fuel cell with a mature pure-culture Geobacter sulfurreducens electroactive biofilm was used for performance optimization by making rapid changes to experimental parameters in microchannels while monitoring their effect using linear sweep voltammetry. A systematic investigation of polarization behavior and evaluation of system resistivity provided important figures of merit and mechanistic insights on the effects of flow rates, concentrations, and temperature. After individual parameters were optimized, a synergistic effect was observed by applying optimal parameters together, resulting in improved current and maximum power densities, compared to stable values at unoptimized conditions. Continued acclimation for just 2 days under these conditions resulted in further improvements to anode area-normalized current and power maxima (10.49 ± 0.23 A m−2 and 2.48 ± 0.27 W m−2), which are among the highest reported in the literature for a microfluidic MFC. In keeping with other accepted normalization protocol using the area separating anode and cathode chambers, the output densities were 64 A m−2 and 15 W m−2, which are near the theoretical maximum outputs achievable with an MFC system.

Brilliant green decolorization by dye decolorizing peroxidase producing bacterium, Achromobacter insolitus isolated from Forest soils of Similipal Biosphere Reserve, Odisha

Dye-decolorizing peroxidases (DyPs) are recently identified superfamily of heme-containing peroxidases which has received much attention for its potential application in dye decolourization. In the current research, six bacterial colonies (SDB1-6) showing lignolytic activity were isolated from forest soils of SBR using a minimal salt medium supplemented with alkali lignin and screened for DyP activity using brilliant green dye supplemented luria bertani agar medium. The highest DyP activity showing bacterium was identified using biochemical and 16SrRNA sequencing and was identified as Achromobacter insolitus. A. insolitus was found to be an efficient strain showing the highest DyP activity of 2.7 U/mL/ml at un-optimized condition. The RSM optimization was conducted to increase the DyP enzyme activity. A. insolitus demonstrated DyP activity of 6.20 U/mL/min with an increase of 2.29 times of enzyme activity in optimal condition of pH 7.0, temperature 25 °C, H2O2 concentration 0.1 mM, and time 24 h. The bacterium was further screened for dye decolorization taking crystal violet, methyl orange, methylene blue, brilliant green and methyl red dyes supplemented in LB medium. The bacterium showed maximum brilliant green degradation ability was analyzed using UV-Vis and FTIR analyses to characterize the degraded product. The highest brilliant green degradation activity of the A. insolitus in the present study could be exploited for bioremediation of brilliant green contaminated industrial effluents in a ecofriendly and cost effective way.

Study on high-altitude ceiling strategy of compression ignition aviation piston engines based on BP-NSGA II algorithm optimization

This paper explores the influence of different turbocharging modes and multi-parameter coordinated control on the performance of compression-ignition (CI) aviation piston engine (APE). Firstly, based on a constructed one-dimensional thermodynamic model of a CI APE, the study investigates the effects of different turbocharging modes and combinations of high and low-pressure stage variable geometry turbines (VGT) on the operational performance of the engine. Subsequently, a novel stepwise approximate multi-objective optimization algorithm is proposed, combining backpropagation neural networks and the non-dominated sorting genetic algorithm II. This algorithm evaluates the influence of multiple control parameters on a two-stage turbocharged engine's performance, achieving a balance between fuel economy and reliability. The research shows that equipping CI APEs with twin VGT for supercharging can notably enhance engine performance, enabling the achievement of favorable power recovery objectives at an altitude of 8000 m. The proposed optimization algorithm exhibits strong predictability and reliability, substantially accelerating the computation speed and reducing the data volume by approximately 95%. At an engine speed of 3887 rpm, compared to the unoptimized conditions, the brake specific fuel consumption of the best scenario at altitudes of 2000 m, 4000 m, 6000 m, and 8000 m is reduced by 7.1%, 7.2%, 8.6%, and 6.9%, respectively.

Modulating the Electrical Properties of Lithium-Doped Zinc Oxide: Interplay of Lithium Content, Oxygen Pressure, and Temperature

This research elucidates the intricate interplay of lithium content, oxygen pressure, and temperature and their influence on the electrical properties of Lithium-doped zinc oxide (LZO). The electrical behavior of zinc oxide (ZnO), a prominent semiconductor material, can be modulated when doped with lithium (Li). Through systematic experimentation, we demonstrate that varying lithium content in the ZnO matrix leads to notable shifts in carrier concentration and mobility, which in turn impacts the material's conductivity and overall electrical performance. Furthermore, oxygen pressure during synthesis plays a pivotal role in defect formation, especially oxygen vacancies, which interact dynamically with lithium dopants to further modulate electrical behavior. Introducing the variable of temperature, our study reveals a synergistic effect, where temperature not only affects intrinsic carrier concentration but also the interactions between lithium dopants and inherent defects in ZnO. Under optimized conditions of oxygen pressure and temperature, the influence of Li content on crystallinity was pronounced, consequently impacting mobility. In contrast, under unoptimized conditions, as Li concentration increased, particularly beyond optimal levels (0.75 mol%), introduced Li atoms assumed the role of compensating centers by capturing or neutralizing carriers, reducing mobility. The findings presented herein provide a comprehensive understanding of how these factors collectively determine the electrical properties of LZO, paving the way for tailored applications in optoelectronic devices, sensors, and more.

Lignin nanoparticles from hydrotropic fractionation of giant reed and eucalypt: Structural elucidation and antibacterial properties

A hydrotropic solution of maleic acid (MA) was exploited to fractionate giant reed (AD) and eucalypt (EUC). The pre-treatment was successful for AD, while it was unsatisfactory for EUC, likely due to unoptimized reaction conditions. Interestingly, lignin nanoparticles (LNP) were produced via spontaneous aggregation following spent liquor dilution. LNP were studied by a plethora of analytical techniques, such as thermogravimetry, electron microscopy, and Nuclear Magnetic Resonance spectroscopy (NMR). Notwithstanding LNP from both AD and EUC showed similar thermal behaviour and morphology, a greater content of aliphatic hydroxyl, carboxyl, guaiacyl and p-hydroxyphenyl moieties was reported for AD-LNP, whereas EUC-LNP had a larger amount of syringyl groups and a higher S/G ratio. Also, the 1H-DOSY NMR indicated the lower size of AD-LNP. Moreover, the LNP were found to negatively impact on the development of several human or plant pathogens, and their bioactivity was related to the occurrence of guaiacyl and p-hydroxyphenyl moieties and a lower the LNP size. We therefore found that MA delignification allows both to achieve high delignification efficiency and to obtain LNP with promising antibacterial effect. Such LNP may help counteracting the antibiotics resistance and sustain the quest for finding sustainable agrochemicals.

Optimization of phytase production by Penicillium oxalicum in solid-state fermentation for potential as a feed additive

The study aims to statistically optimize the phytase production by Penicillium oxalicum PBG30 in solid-state fermentation using wheat bran as substrate. Variables viz. pH, incubation days, MgSO4, and Tween-80 were the significant parameters identified through the Plackett-Burman design (PBD) that majorly influenced the phytase production. Further, central composite design (CCD) method of response surface methodology (RSM) defined the optimum values for these factors i.e., pH 7.0, 5 days of incubation, 0.75% of MgSO4, and 3.5% of Tween-80 that leads to maximum phytase production of 475.42 U/g DMR. Phytase production was also sustainable in flasks and trays of different sizes with phytase levels ranging from 394.95 to 475.42 U/g DMR. Enhancement in phytase production is 5.6-fold as compared to unoptimized conditions. The in-vitro dephytinization of feed showed an amelioration in the nutritive value by releasing inorganic phosphate and other nutrients in a time-dependent manner. The highest amount of inorganic phosphate (33.986 mg/g feed), reducing sugar (134.4 mg/g feed), and soluble protein (115.52 mg/g feed) was achieved at 37 °C with 200 U of phytase in 0.5 g feed for 48 h. This study reports the economical and large-scale production of phytase with applicability in enhancing feed nutrition.

Production and purification of high activity β-mannanase from Streptomyces rochei and enzymatic hydrolysis of sugar palm fruit for galactomannan oligosaccharide (GMOS) production

The high activity of β-mannanase produced by Streptomyces rochei was achieved by enhancing the activity using a combination of the OFAT and the CCD of RSM method.The activity of β-mannanase produced by Streptomyces rochei was obtained to be 201.63 U/mL using OFAT method. Furthermore, the CCD of RSM optimized several process parameters such as nitrogen, carbon, and (KH2PO4) concentration. The maximum β-mannanase yield was nearly 7.5 times (460 U/mL) higher than the unoptimized condition (61.09 U/mL). The purified β-mannanase had a molecular weight of approximately 35.0 kDa and showed optimal activity at a pH of 6.0 and a temperature of 60 °C. Manannase could hydrolyze galactomannan-rich mannan polymers such as sugar palm fruit and other commercial mannans to create GMOS. For further research, developing a recombinant mannanase, scaling up the production of mannanase and also the study of GMOS activity for the health industrial applications are necessary. Additionally, it is important to conduct in vivo and in vitro assays to examine the activity of GMOS for potential application in the health industry.

Optimization of limonin invertase production by scaling up aspergillus tabingensis UA13 fermentation to a 5-liter scale.

The enzymatic approach is a highly effective and the major scientific method to eliminating bitter components in citrus-derived products nowadays. Microbial production of limonin invertase stands out due to its pivotal role in the removal of the bitter substance, limonin. The optimization of fermentation parameters and the study of scale-up fermentation are imperative for product commercialization. In this study, we focused on optimizing stirring speed, fermentation temperature, and initial pH to enhance the growth and limonin invertase production by the Aspergillus tabin (A. tabin) strain UA13 in a 5-liter stirred-tank bioreactor. Our results revealed the following optimal parameters are: a stirring speed of 300rpm, a fermentation temperature of 35 °C and a pH 5.0. Under these optimized conditions, the limonin invertase activity reached its peak at 63.38U mL-1, representing a 1.67-fold increase compared to the unoptimized conditions (38.10U mL-1), while also reducing the fermentation duration by 12 hours. Furthermore, our research demonstrated that limonin invertase effectively hydrolyze limonin in grapefruit juice, reducing its content from 13.28μg mL-1 to 2.14μg mL-1, as determined by HPLC, resulting in a 6.21-fold reduction of the bitter substance.

Design of a double-layer composite ceramic and its brazing with niobium

A double-layer composite ceramic incorporating excellent mechanical and joining properties was designed by optimizing the composition of the TiB2–TiC–SiC ceramic. First, the ceramic composition that optimized the mechanical properties was explored by fabricating TiB2–TiC–SiC ceramics with four different compositions. The results showed that the flexural strength of the composite ceramics increased with the increase of TiC component in the composite ceramics, albeit with a slight decrease in fracture toughness. The TiB2–20TiC–20SiC (vol. %) ceramic exhibited excellent mechanical properties with a hardness of 20.6 GPa, fracture toughness of 6.21 MPa ·m1/2, and flexural strength of 486 MPa. Then, the four TiB2–TiC–SiC composite ceramics were brazed with Nb to investigate the ceramic composition that optimized the joining performance. As the TiC component in the composite ceramics increased, the reduction of the Nb3B2 phase and the increment of the (Ti, Nb)2Ni phase within the reaction zone along the ceramic side can be noticed, and the width of this reaction zone decreased from 29 μm to 15 μm. The TiB2–5TiC–20SiC (vol. %) ceramic demonstrated promising joining performance with a maximum shear strength of 229 MPa for its brazed joint with Nb. Finally, a double-layer composite ceramic with the surface composition of TiB2–5TiC–20SiC and base composition of TiB2–20TiC–20SiC was prepared. The maximum shear strength of 248 MPa was achieved by brazing the double-layer composite ceramic with Nb at a temperature of 1433 K for 10 min, representing a 39 % improvement over the unoptimized condition.

Micrococcus luteus Tarafından Sentezlenen Keratinaz Enziminin Taguchi DOE Yöntemi Kullanılarak Optimizasyonu

Keratinase is an important enzyme used for degradation of the keratinous wastes, especially slaughterhouse and poultry-derived wastes, that cause environmental pollution. In the current study, optimum conditions for keratinase production by Micrococcus luteus Y23-18 strain were investigated using Taguchi DOE L9 orthogonal array. For this purpose, the selected environmental factors were initial pH, incubation temperature and time. The optimal conditions were obtained as pH 9.5, temperature 30˚C and 3 days. The obtained results showed that keratinase activity was enhanced approximately 2.3-folds (34.95 U mL-1) when compared with the unoptimized conditions (15.33 U mL-1). As a result, M. luteus Y23-18 is an effective keratinase producer microorganism and Taguchi design of experiment is a useful tool for optimization.

Isolation and Characterization of Newly Laccase-Producing Endophytic Fungi in Submerged Cultures from Calotropis gigantean Plant Leaves

The aim of the study to isolate and identify new laccase sources from an endophytic fungal source that could be used as a weapon foreliminating and detoxifying contaminants found in wastewater and aquatic habitats. Isolation was done from Calotropis gigantean plantleaves from different locations of paper mill effluents from the “Raipur” region of Chhattisgarh, India. Positive isolates were obtainedwith a dark brown color below and surrounding the fungal colony due to guaiacol oxidation on potato dextrose agar. One potentendophytic fungal isolate that produces laccase is identified as Aspergillus turcosus by using the internal transcribed spacer (ITS) andBLAST analysis. After optimization, maximum laccase production was obtained at the following conditions: medium (Czapeck Dox Broth),carbon source (sucrose), nitrogen source (sodium nitrate), pH (6), activator tannic acid (20 mM), incubation period (35°C) and duration(8 days) with 3 (8 mM fermentation) disc inoculums. The maximum laccase activity was obtained at 65 U mL-1 in submerged optimizedconditions, which was more than two fold compared to the unoptimized conditions. As estimated by SDS-PAGE, The molecular massof the monomer of pure laccase was determined to be 66 kDa. After five days of treatment with the laccase of A. turcosus, the syntheticdyes phenol red, bromophenol blue, methyl orange, and Congo red lose their colour. Clearance rates for chemical oxygen demand were59.46 and 48.57%, and phenolic contaminants were 80 and 22.3% in coal and textile effluents during the required treatment periods,respectively. One novel and potent laccase-producing endophytic fungus was successfully isolated, which can be utilized as a laccaseproducingsource for various industrial applications.

A promising microbial α-amylase production, and purification from Bacillus cereus and its assessment as antibiofilm agent against Pseudomonas aeruginosa pathogen

Background and aimThe purpose of the current study is to isolate a heavily amylase-producing bacteria of the genus Bacillus from soil samples, optimize the production of the enzyme, purify it, and evaluate its activity against biofilm-producing bacteria. A total of 12 soil samples were collected and screened for promising Bacillus species with good amylolytic activity. Isolation was done by serial dilution and plating technique and amylolytic activity was determined by starch agar plate method. Among the 12 Bacillus isolates recovered from soil samples, 7 showed positive α-amylase production. The best isolate that recorded the greatest amylolytic activity was selected for further studies. This isolate was identified by 16S rRNA sequencing as Bacillus cereus and registered under gene bank accession number OP811897. Furthermore, the α-amylase enzyme was produced by a submerged fermentation technique using best production media and partially purified by ammonium sulfate and chilled ethanol and molecular weight had been determined by SDS-PAGE gel electrophoresis. The production of α-amylase was optimized experimentally by one-factor at a time protocol and statistically by Plackett–Burman design as well as RSM CCD design. Data obtained from OFAT and CCD revealed that α-amylase activities were 1.5- and twofold respectively higher as compared to un-optimized conditions. The most significant factors had been identified and optimized by CCD design.ResultsAmong the eleven independent variables tested by PBD, glucose, peptone, (NH4)2SO4, and Mg SO4 were the most significant parameters for α-amylase production with an actual yield of 250U/ml. The best physical parameters affecting the enzyme production were incubation time at 35 °C, and pH 5.5 for 48 h. The partially purified enzyme with 60% ammonium sulphate saturation with 1.38- fold purification showed good stability characteristics at a storage temperature of 4 °C and pH up to 8.5 for 21 days. Antibiofilm activity of purified α-amylase was determined against Pseudomonas aeruginosa (ATCC 35659) by spectrophotometric analysis and CLSM microscopic analysis. Results demonstrated biofilm inhibition by 84% of the formed Pseudomonas biofilm using a microtiter plate assay and thickness inhibition activity by 83% with live/Dead cells percentage of 17%/83% using CLSM protocol.ConclusionsA highly stable purified α-amylase from B. cereus showed promising antibiofilm activity against one of the clinically important biofilm-forming MDR organisms that could be used as a cost-effective tool in pharmaceutical industries.

Performance evaluation and yield optimization of L-glutaminase free L-asparaginase from seaweed-associated bacteria

Gracilaria dura associated bacterial diversity revealed 75 isolates, which were screened for L-asparaginase (LA) production. Out of the three positive isolates, upon secondary screening, the strain 4T1C26E identified as Bacillus licheniformis registered the highest (25.2 IU ml−1) LA activity. This isolate was further subjected to yield improvement by optimizing process parameters through Response Surface Methodology (RSM) and Artificial Neural Networking-Particle Swarm Optimization (ANN-PSO). A 2.5-fold increase in production by using RSM while 4-fold increase by using ANN with respect to un-optimized conditions could be achieved. In the preliminary toxicity analysis on the standard animal model Caenorhabditis elegans, the worms treated with crude LA showed similar growth pattern to the control worms marking the enzyme safe for human applications. The important benefit of LA obtained here is that it possesses no L-glutaminase activity and is free of endotoxins which is suitable for downstream processing thereby reducing chances of the immunogenic responses.

Screening and optimization of Manganese peroxidase (MnP) production by Pseudoduganella violacea (SMB4), a bacterial isolate from Similipal Biosphere Reserve, Odisha and evaluation of Maillard reaction products degradation

The Maillard reaction products (Melanoidin) are major environmental pollutants of the distillery and fermentation industries. Manganese peroxidase (MnP) was found to be an efficient ligninolytic enzyme capable of degrading Maillard products. MnP can convert Mn2 ions in wood and soils to the more reactive Mn2+ ions. The current study aims to isolate MnP producing bacteria from Similipal Biosphere Reserve (SBR), Odisha, and determine its biodegradation ability towards millards products. In total 10 ligninolytic bacterial colonies were isolated from the soil sample of SBR and their MnP activity was screened using phenol red dye as an indicator. The isolate, SMB4 was found to be the most efficient MnP-producing bacterium showing the highest MnP activity of 3.89 U/ml/min in un-optimized conditions. The bacterium was identified as Pseudoduganella violacea based on morphological, biochemical and molecular characterization. MnP activity of SMB4 was optimized using response surface methodology. Under optimized conditions SMB4 showed MnP activity of 6.12 U/ml/min which is 1.57 times from un-optimized condition. The isolate SMB4 was found to show significant decolorization of maillards products up to 83.68 % at temperature 37 °C within 192 h of incubation. The degraded product was analyzed using UV–vis and FTIR analyses. The current investigation suggests that MnP produced by Pseudoduganella violacea may be successfully exploited for bioremediation purposes to degrade Maillard products.