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Organic waste bioprocessing for production of useful products are increasing due to fossil fuel depletion, problems with waste management, and the requirement for biodegradable plastics. Lactic acid (LA) is important in foods, polymer beverages, cosmetics, and medicine applications. However, the main challenge in the large-scale processing of LA is the enhanced production and productivity using low-cost resources. In this study, Enterococcus faecium WH51-1, a newly obtained thermo-alkali tolerant LA bacterium, was used for LA production from corn-steep water (CSW) as raw material. The optimal culture conditions and medium components were established. Different concentrations of yeast extract (YE) and pH values were investigated with highest LA production of 48.2 ± 2.7 g/L at a yield of 0.89 ± 0.04 g/g-consumed sugars and a productivity of 0.50 ± 0.03 g/L.h at pH 8.5 without YE supplementation. A central composite design (CCD) was utilized to determine the high LA concentrations at optimal values for the process variables (sugar concentrations, temperature, inocula sizes, pH value, and YE concentration). The model was realized with an acceptable fit. The optimization of the factors was carried out by normal probability plots, interaction-plots, incorporating effect plots, analysis of variance (ANOVA), surface plots, Pareto charts, and contour plots. All the parameters were influenced at a 5% significance level. Additionally, some of the possible interactions between these parameters also influenced the production process. A regression model was suggested and fitted the experimental data very well. The results of this work investigated that LA synthesized of the optimized-fermentation conditions was 10% greater than classical optimization methods. This study presented a green “free nutrient” and cost-effective utilization of corn steep effluent as a cheap alternative substrate for biorefinery to lactic acid. Graphical Abstract

The textile and leather industry produces large amounts of wastewater that contains high levels of chemicals and other pollutants, incorporated during the processing stages. We evaluated the efficacy of green synthesized iron oxide (α-Fe2O3) and magnesium oxide (MgO) nanoparticles (NPs) for wastewater treatment of crude textile and tannery effluents. Green synthesis of α-Fe2O3-NPs and MgO-NPs was conducted using the newly obtained Aspergillus carbonarious strain D-1. The optimization of the physicochemical parameters for the biosynthesis of NPs, including incubation periods, contact time, pH, temperature, and precursor concentrations, were assessed. The characterization of NPs obtained under optimal conditions was evaluated using UV–visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, dynamic light scattering (DLS), and Fourier Transform Infrared (FT-IR) Spectroscopy. The optimal concentration for efficient textile/tannery wastewater decolorization was determined to be 100 mg NPs after eight hours for α-Fe2O3-NPs and after four hours for MgO-NPs. Under these conditions, chemical oxygen deman (COD), pH value, total dissolved solids (TDS), total suspended solids (TSS), and conductivity were greatly reduced as compared to control for crude textile wastewater. GC–MS analysis of NPs-treated textile wastewater revealed that some major compounds were greatly diminished, bio-transformed, or completely degraded. MgO and α-Fe2O3 NPs exhibited a high capacity to reduce the COD of tannery wastewater by 97.5% and 95.0%, respectively. Hematite NPs exhibited higher removal capacity for TDS, TSS, and conductivity compared to MgO-NPs. MgO and hematite NPs exhibited high capacities to remove Cr, with MgO redcing Cr by 87.06 and hematite NPs reducing Cr by 75.4%. MgO-NPs were more effective than α-Fe2O3-NPs at removing Pb, Ni, and Cd.

Liquid microbial inoculants have recently received great attention due to their vital roles for sustainable agricultural practices. However, long-term conservation under ambient temperature conditions and deleterious environmental factors might negatively impact microbial cell survival and limit their efficacy in the field. Thus, developing efficient liquid formulation providing prolonged survival of rhizobia in the final product and after an application is crucial. Therefore, this study investigates the effect of various additives on the long-term survival of rhizobia stored in liquid cultures at room temperature (25 °C) for 12 months. Various yeast sucrose media amended with polyvinylpyrrolidone (PVP) or gum arabic as colloidal agents in combination with ectoine (as a compatible solute) and/or glycerol were evaluated. A dramatic decline in viable cell count was obtained in formulas amended only with PVP from Log 8.5 to Log 5 in the first six months and then to Log 1.5 after 12 months. In contrast, rhizobia stored at PVP-based formulas amended with 10 mg L‒1 ectoine exhibited almost constant survival level till the end of the storage period. The same trend was obtained using formulas based on gum arabic as a colloidal dispersing agent; however, less decline in cell count using a formula containing gum arabic alone as compared to using PVP. On the other hand, PVP based formulas exhibited higher viscosity compared with another formula. Increased viscosity till the 8th month of storage was achieved in the presence of ectoine indicating the increase of exopolymeric substances production. Electrophoretic protein pattern of rhizobial cells (stored for 12 months) exhibited several low molecular weight protein bands in cells stored in PVP based formula with ectoine as compared to the other treatments. Thus, the amendment of the liquid formulation of rhizobia bioinoculant with PVP plus ectoine not only improved cell survival but also enhanced the culture viscosity and consequently ameliorate the colonization and performance of rhizobial inoculants.

In the current work, date wastes were used for lactic acid (LA) production under thermo-alkaline conditions to overcome some fermentation challenges. Amongst 27 bacterial isolates that produced LA from date juice, isolate D-218 exhibited better growth stability and LA production under various stressed conditions. This isolate was characterized as Bacillus coagulans D-218 using physiological and molecular identification methods. In batch fermentation mode, strain D-218 could not completely utilize 80 g/L of the total sugar and produced only 45.8 ± 2.8 g/L of LA at LA productivity of 0.214 g/L.h and high residual sugar (29.2 g/L) was unutilized in the fermentation media. Different repeated batch fermentations with different initial sugar concentrations and gradual increase in sugar concentrtions were conducted to maximize LA productivity. Starting with 60 g/L of total sugar, four runs of repeated batch fermentations were conducted that enhanced the LA productivity (70%) to 0.49 g/L.h. Another 9 runs were initiated with 40 g/L which further improved LA productivity that reached up to 0.77 g/L.h. Surprisingly, initiating fermentations with 20 g/L of total sugar successfully attained long-term fermentation (18 runs) with high LA yield and productivity without carbon loss of initiated startup sugar of date waste. In this process, strain D-218 could completely consume 80 g/L sugars with high LA production titer (72.9 ± 0.56 g/L), yield (0.92 g/g), and productivity (0.71 g/L.h). This study is the first to exploit date waste in a cost-effective system for high-titer lactic acid production under thermo-alkaline conditions (pH 9.0; 50 °C) and to report repeated batch fermentation for LA production from date wastes.

Microbial bioconversion of agro-industrial wastes to green chemicals has become an important objective in industrial biotechnology for lowering the product costs. Therefore, in this work, beet molasses was used as a potential raw material for lactic acid (LA) production by a newly isolated bacterium, Enterococcus faecium S6. The pretreatment of molasses with EDTA has exhibited the highest effectiveness for bioconversion to LA. The optimal medium components and culture conditions were established. Supplementation of molasses by yeast extract (YE) and ammonium chloride have achieved LA production of 11.90 g/L at a yield of 0.71 g/g-consumed sugars and a productivity of 0.33 g/L/h. Various approaches were used for the optimization of relevant factors affecting l-LA production in batch fermentations. Using classical “one-factor-at-a-time” approach, the optimal factors were as follows: sugar concentration, 40 g/L; pH, 7.0; 40 °C; and inoculum size, 10% (v/v) achieving LA at 29.7 g/L. The effects of these five fermentation parameters were further investigated by response surface methodology (RSM) to maximize LA production. The optimized fermentation conditions by RSM were as follows: sugar concentration, 65 g/L; YE, 0.625 g/L; temperature, 42 °C; pH, 6.75; and inoculum size, 9.5% (v/v) that achieved LA production of 41.5 g/L. Further improvements were achieved using repeated batch fermentation that has conducted for 16 runs. Using seed culture pre-adapted to the actual fermentation conditions in repeated batch fermentation led to enhanced LA production with a shorter process time compared to batch fermentation. These results achieved a maximum LA of 64.7 g/L with high yield (0.94 g/g of consumed sugars) and productivity (2.16 g/L/h). This study presented a cost-effective and long-term fermentative production of LA from beet molasses.

In this study, a non-sterile (open) continuous fermentation (OCF) process with no-carbon loss was developed to improve lactic acid (LA) productivity and operational stability from the co-utilization of lignocellulose-derived sugars by thermophilic Enterococcus faecium QU 50. The effects of different sugar mixtures on LA production were firstly investigated in conventional OCF at 50°C, pH 6.5 and a dilution rate of 0.20 hr-1 . The xylose consumption ratio was greatly lower than that of glucose in fermentations with glucose/xylose mixtures, indicating apparent carbon catabolite repression (CCR). However, CCR could be efficiently eliminated by feeding solutions containing the cellobiose/xylose mixture. In OCF at a dilution rate ca. 0.10 hr-1 , strain QU 50 produced 42.6 g L-1 of l-LA with a yield of 0.912 g g-1 -consumed sugars, LA yield of 0.655 g g-1 based on mixed sugar-loaded, and a productivity of 4.31 g L-1 hr-1 from simulated energy cane hydrolyzate. In OCF with high cell density by cell recycling, simultaneous and complete co-utilization of sugars was achieved with stable LA production at 60.1 ± 3.25 g L-1 with LA yield of 0.944 g g-1 -consumed sugar and LA productivity of 6.49 ± 0.357 g L-1 hr-1 . Besides this, a dramatic increase in LA yield of 0.927 g g-1 based on mixed sugar-loaded with prolonged operational stability for at least 500 hr (>20 days) was established. This robust system demonstrates an initial green step with a no-carbon loss under energy-saving toward the feasibility of sustainable LA production from lignocellulosic sugars.

Nile-Tilapia (Oreochromis niloticus) aquaculture represents one of the most important cultivation species in Egypt. However, Tilapia fish farming is challenged by some problems. Of those, the presence of bacterial pathogens resulting in high fish mortalities and huge economic losses. Thus, the current investigation aimed to isolate, identify, and characterize the pathogenic bacteria from Nile tilapia fish farm in El-Abassa village, Egypt and to investigate their antibiotic susceptibility as a primary step for controlling diseases. 182 bacterial isolates were obtained from one hundred Tilapia fish samples. The microbiological and biochemical analysis of the examined fish indicated the presence of only 5 bacterial genera. Three of them are Gram-negative bacteria (representing 86.26% of total isolates) including Aeromonas spp. (46.70 %), Pseudomonas spp. (23.08 %), and Vibrio spp. (16.48 %). While two genera are Gram-positive bacteria (representing 13.74% of the total isolates) including Streptococcus spp. (8.79 %) and Staphylococcus spp. (4.95 %). This indicates that Gram-negative bacteria are the main cause of high fish mortalities in the studied area while Aeromonas hydrophila exhibited the highest prevalence in infected tilapia. Antibiogram test revealed high levels of resistance expressed by all isolates to ampicillin, amoxicillin, and erythromycin. On the other hand, norfloxacin was effective against all isolated bacteria followed by ciprofloxacin; therefore, norfloxacin should be recommended as a supplement in fish fed-diets to control the bacterial infection. Establishing effective control methods for pathogenic isolates would greatly enhance fish production.

Endophytic bacteria colonize plants and live inside them for part of or throughout their life without causing any harm or disease to their hosts. The symbiotic relationship improves the physiology, fitness, and metabolite profile of the plants, while the plants provide food and shelter for the bacteria. The bacteria-induced alterations of the plants offer many possibilities for biotechnological, medicinal, and agricultural applications. The endophytes promote plant growth and fitness through the production of phytohormones or biofertilizers, or by alleviating abiotic and biotic stress tolerance. Strengthening of the plant immune system and suppression of disease are associated with the production of novel antibiotics, secondary metabolites, siderophores, and fertilizers such as nitrogenous or other industrially interesting chemical compounds. Endophytic bacteria can be used for phytoremediation of environmental pollutants or the control of fungal diseases by the production of lytic enzymes such as chitinases and cellulases, and their huge host range allows a broad spectrum of applications to agriculturally and pharmaceutically interesting plant species. More recently, endophytic bacteria have also been used to produce nanoparticles for medical and industrial applications. This review highlights the biotechnological possibilities for bacterial endophyte applications and proposes future goals for their application.

Potential high bio-deterioration of certain microorganisms due to their metabolic activities on organic materials causes serious problems in the conservation of cultural heritage. This study focuses on establishing an efficient conservation strategy against microbial deterioration using biosynthesized nanoparticle (NPs). Isolation, identification, and characterization of microorganisms involved in deterioration of archaeological manuscript dating back to 17th century (1677 A.D) were conducted. Eleven bacterial species and fifteen fungal species were obtained and identified using 16S rRNA and ITS sequences, respectively. All strains exhibited potent cellulolytic activity. Bacillus subtilis strain (B3) and Penicillium chrysogenum strain (F9) achieved the highest cellulolytic activity amongst obtained bacterial and fungal strains. Paper models conservation effect of biosynthesized silver and zinc oxide NPs against strain (B3) and strain (F9) was evaluated. Microbial growth inhibition, color change according to CIE L*a*b* color space, fourier transform infrared spectroscopy (FT-IR) were assessed. Furthermore, morphology and the elemental component of paper models were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Silver NPs achieved better results than zinc oxide NPs for paper preservation. Application of 1.0 or 2.0 mM silver NPs exhibited the best preservation effect on the paper models achieving 100% microbial inhibition (bacteria and fungi, respectively). Moreover, NPs-treated paper models showed slight color change and exhibited similar structural analysis as original papers. These results showed the potentiality of this green strategy to be applied for conservation of cellulose-constructed cultural heritage.

Historic cultural heritage and archival manuscripts have a significant importance worldwide and efforts should be considered to preserve such property for as long as possible. The current study aimed to establish a non-toxic, and eco-friendly conservation strategy for retarding paper biodeterioration. To this end, fungal isolates associated with the biodeteriorated paper manuscripts of the historical book “DESCRIPTION DE L´EGYPTE” dating back to 1823 A.D were isolated. These isolates were identified as Asperigllus niger, Aspergillus flavus, Penicillium chrysogenum and Alternaria alternata and then evaluated for cellulolytic activities. Amongst them, Aspergillus niger A2 exhibited the highest cellulase activity. In in vitro study using filter papers as model, the suppressive effect of biosynthesized silver and zinc oxide nanoparticles (NPs) on A. niger A2 bioderteriorant activity was evaluated. Biosynthesized Ag-NPs and ZnO-NPs were characterized by UV-Vis spectroscopy, X-ray diffraction patterns (XRD), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FT-IR). Color changes, tensile strength, FT-IR-spectroscopy, and scanning electron microscopy of NPs-treated papers were examined. Treatments with 2 mM Ag-NPs and 2 mM ZnO-NPs exhibited the best conservation effect on treated papers and alleviated cellulose degradation. Furthermore, this treatments enhanced tensile strength and preserved the original morphology of paper fibers. These results introduced a potential approach for historical documents conservation against fungal biodeterioration through NPs sprays. It can be also used for preparing anti-biodeterioration paper for expected manuscripts uses.

The incidence of Extended-spectrum β-lactamase (ESBL)-encoding genes (blaCTX-M and blaTEM) among Gram-negative multidrug-resistant pathogens collected from three different countries was investigated. Two hundred and ninety-two clinical isolates were collected from Egypt (n = 90), Saudi Arabia (n = 162), and Sudan (n = 40). Based on the antimicrobial sensitivity against 20 antimicrobial agents from 11 antibiotic classes, the most resistant strains were selected and identified using the Vitek2 system and 16S rRNA gene sequence analysis. A total of 85.6% of the isolates were found to be resistant to more than three antibiotic classes. The ratios of the multidrug-resistant strains for Egypt, Saudi Arabia, and Sudan were 74.4%, 90.1%, and 97.5%, respectively. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa showed inconstant resistance levels to the different classes of antibiotics. Escherichia coli and Klebsiella pneumoniae had the highest levels of resistance against macrolides followed by penicillins and cephalosporin, while Pseudomonas aeruginosa was most resistant to penicillins followed by classes that varied among different countries. The isolates were positive for the presence of the blaCTX-M and blaTEM genes. The blaCTX-M gene was the predominant gene in all isolates (100%), while blaTEM was detected in 66.7% of the selected isolates. This work highlights the detection of multidrug-resistant bacteria and resistant genes among different countries. We suggest that the medical authorities urgently implement antimicrobial surveillance plans and infection control policies for early detection and effective prevention of the rapid spread of these pathogens.

Effective lactic acid (LA) production from lignocellulosic biomass materials is challenged by several limitations related to pentose sugar utilization, inhibitory compounds, and/or fermentation conditions. In this study, a newly isolated Bacillus coagulans strain Azu-10 was obtained and showed homofermentative LA production from xylose with optimal fermentation conditions at 50 °C and pH 7.0. Growth of strain Azu-10 and LA-fermentation efficiency were evaluated in the presence of various lignocellulose-derived inhibitors (furans, carboxylic acids, and phenols) at different concentrations. Furanic lignocellulosic-derived inhibitors were completely detoxified. The strain has exhibited high biomass, complete xylose consumption, and high LA production in the presence of 1.0‒4.0 g/L furfural and 1.0‒5.0 g/L of hydroxymethyl furfural, separately. Moreover, strain Azu-10 exhibited high LA production in the presence of 5.0–15.0 g/L acetic acid, 5.0 g/L of formic acid, and up to 7.0 g/L of levulinic acid, separately. Besides, for phenolic compounds, p-coumaric acid was most toxic at 1.0 g/L, while syringaldehyde or p-hydroxybenzaldehyde, and vanillin at 1.0 g/L did not inhibit LA fermentation. The present study provides an interesting potential candidate for the thermophilic LA fermentation from lignocellulose-derived substrates at the industrial biorefinery level.

Background The simultaneous and effective conversion of both pentose and hexose in fermentation is a critical and challenging task toward the lignocellulosic economy. This study aims to investigate the feasibility of an innovative co-fermentation process featuring with a cell recycling unit (CF/CR) for mixed sugar utilization. A l-lactic acid-producing strain Enterococcus mundtii QU 25 was applied in the continuous fermentation process, and the mixed sugars were utilized at different productivities after the flowing conditions were changed. A mathematical model was constructed with the experiments to optimize the biological process and clarify the cell metabolism through kinetics analysis. The structured model, kinetic parameters, and achievement of the fermentation strategy shall provide new insights toward whole sugar fermentation via real-time monitoring for process control and optimization. Results Significant carbon catabolite repression in co-fermentation using a glucose/xylose mixture was overcome by replacing glucose with cellobiose, and the ratio of consumed pentose to consumed hexose increased significantly from 0.096 to 0.461 by mass. An outstanding product concentration of 65.2 g L−1 and productivity of 13.03 g L−1 h−1 were achieved with 50 g L−1 cellobiose and 30 g L−1 xylose at an optimized dilution rate of 0.2 h−1, and the cell retention time gradually increased. Among the total lactic acid production, xylose contributed to more than 34% of the mixed sugars, which was close to the related contents in agricultural residuals. The model successfully simulated the transition of sugar consumption, cell growth, and lactic acid production among the batch, continuous process, and CF/CR systems. Conclusion Cell retention time played a critical role in balancing pentose and hexose consumption, cell decay, and lactic acid production in the CF/CR process. With increasing cell concentration, consumption of mixed sugars increased with the productivity of the final product; hence, the impact of substrate inhibition was reduced. With the validated parameters, the model showed the highest accuracy simulating the CF/CR process, and significantly longer cell retention times compared to hydraulic retention time were tested.

This study addresses the impacts of metabolites from different microbial taxa on the fabrication and multifunctional biological properties of spherical silver nanoparticles (Ag-NPs). Three microbial taxa, a bacterial (Bacillus cereus A1-5), actinomycetes (Streptomyces noursei H1-1), and fungal (Rhizopus stolonifer A6-2) strains were used for Ag-NPs biosynthesis, whereas Streptomyces noursei is demonstrated for the first time. These isolates were identified using either 16S rRNA or ITS gene sequencing. Characterization of Ag-NPs was done using color change analysis, Uv-Vis spectroscopy, FT-IR spectroscopy, XRD, TEM, SEM-EDX, DLS, and Zeta potential analysis. All biosynthesized NPs exhibited spherical shape with different sizes ranged from 6‒50 nm, 6–30 nm and 6–40 nm for NPs obtained by A1-5, H1-1 and A6-2, respectively. The crystalline center cubic face of Ag-NPs was confirmed using XRD at 2θ values 38.08o, 44.27o, 64.41o and 77.36o. FT-IR analysis revealed varied intense absorption peaks for biomolecules required for NPs synthesize by each microbial strain. The stability of spherical Ag-NPs was confirmed due to highly DLS negative surface charge of ‒17.5mV, ‒18.9mV, and ‒15.6mV for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Ag-NPs exhibited a broadspectrum of antibacterial activity against Gram-positive and Gram-negative bacteria with varied effectiveness. They also exhibited a cytotoxic effect against cancer cell line (caco-2) in a dose-dependent pattern with IC50 of 8.9 ± 0.5, 5.6 ± 3.0, 11.2 ± 0.5 μg/ml for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Moreover, these spherical Ag-NPs showed larvicidal activity against the 3rd instar larvae of the dengue vector Aedes aegypti., Materials Science; Nanotechnology; Agriculture; Spherical silver nanoparticles; Ag-NPs biosynthesis; Antibacterial; Antitumor activities; Larvicidal; Aedes aegypti

In this study, the production of lactic acid (LA) from beet molasses, a by-product of the beet sugar industry was investigated using newly isolated potential lactic acid bacteria. Isolate ds10 was selected amongst 138 bacterial isolates obtained from natural sources. This isolate was identified as Enterococcus hirae ds10 based on morphological, biochemical and molecular characteristics using 16S rRNA sequence. Direct utilization of molasses achieved low LA production at 2.01 g L‒1. Different molasses’ pretreatment methods were investigated. Molasses treated with EDTA were considered as the best substrate achieving effective LA production at 11.39 ± 2.07 g L‒1. Furthermore, medium constituent was optimized, where supplementation of 0.5% (w/v) ammonium chloride and 0.05% (w/v) yeast extract exhibited the best fermentation medium. Further optimization of fermentation factors was performed by using one-factor-at-a-time (OFAT) and response surface Minitab 18 software approaches. OFAT technique achieved the maximum LA production of 25.4 ± 0.42 g L‒1 after 24 h at sugar molasses conc., 4% (w/v); inoculum size, 10% (v/v); pH, 8.0; and temperature, 40 °C. Whereas, response surface Minitab 18 software approach resulted in a 60% increase in LA production achieving 40.69 g L‒1 at 60 g L‒1 sugar concentration, 0.625 g L‒1 yeast extract, 40 °C, pH 8 and 9.5% inoculum size. The optimization strategy in this study could achieve a 20-fold increase in LA production as compared to initial production.

Enterococcus mundtii QU25, a non-dairy lactic acid bacterium of the phylum Firmicutes, is capable of simultaneously fermenting cellobiose and xylose, and is described as a promising strain for the industrial production of optically pure l-lactic acid (≥ 99.9%) via homo-fermentation of lignocellulosic hydrolysates. Generally, Firmicutes bacteria show preferential consumption of sugar (usually glucose), termed carbon catabolite repression (CCR), while hampering the catabolism of other sugars. In our previous study, QU25 exhibited apparent CCR in a glucose-xylose mixture phenotypically, and transcriptional repression of the xylose operon encoding initial xylose metabolism genes, likely occurred in a CcpA-dependent manner. QU25 did not exhibit CCR phenotypically in a cellobiose-xylose mixture. The aim of the current study is to elucidate the transcriptional change associated with the simultaneous utilization of cellobiose and xylose. To this end, we performed RNA-seq analysis in the exponential growth phase of E. mundtii QU25 cells grown in glucose, cellobiose, and/or xylose as either sole or co-carbon sources. Our transcriptomic data showed that the xylose operon was weakly repressed in cells grown in a cellobiose-xylose mixture compared with that in cells grown in a glucose-xylose mixture. Furthermore, the gene expression of talC, the sole gene encoding transaldolase, is expected to be repressed by CcpA-mediated CCR. QU25 metabolized xylose without using transaldolase, which is necessary for homolactic fermentation from pentoses using the pentose-phosphate pathway. Hence, the metabolism of xylose in the presence of cellobiose by QU25 may have been due to 1) sufficient amounts of proteins encoded by the xylose operon genes for xylose metabolism despite of the slight repression of the operon, and 2) bypassing of the pentose-phosphate pathway without the TalC activity. Accordingly, we have determined the targets of genetic modification in QU25 to metabolize cellobiose, xylose and glucose simultaneously for application of the lactic fermentation from lignocellulosic hydrolysates.

We previously reported that Aeromonas hydrophila exhibited the highest prevalence rate amongst 182 bacterial strains isolated from naturally diseased Nile tilapia (Oreochromis niloticus) collected from El-Abassa Fish Farm, Egypt (Hassan et al., Egypt. J. Aquac., 10, 23–43, 2020). The overuse of antibiotics for controlling diseases has led to acquired antibiotics resistance of aquatic bacteria, besides the developments of human, aquatic animal and environmental risks arising from residual antibiotics. Therefore, the evaluation of safe alternative phytotherapies is of great importance. This study was conducted to evaluate and compare growth performance and immune potentiating activities of moringa (Moringa oleifera) leaves extract (Moringa LE) and pomegranate (Punica granatum) peel extract (Pomegranate PE) on Nile tilapia against infection with a pathogenic bacterium, Aeromonas hydrophila. A total of 150 Oreochromis niloticus were randomly divided into 5 groups to be fed at 3% of body weight with isonitrogenous/isoenergetic diets supplemented with Moringa LE at 0.15 and 0.25% kg−1 or Pomegranate PE at of 0.3 and 0.5% kg−1, separately. Growth performance was significantly affected by Moringa LE as compared with the control group without supplementation of plant extract, while Pomegranate PE levels did not affect growth performance. Maximum average daily gains, specific growth rate, albumin, globulin, total protein, A/G ratio, alanine amino transaminase (ALT), aspartate amino transaminase (AST), cholesterol, triglyceride, creatinine, urea, and lysozyme were analyzed. Antioxidant enzymes of catalase and superoxide dismutase were also evaluated in liver tissues. After feeding experiment, the results indicated that the addition of Moringa LE and Pomegranate PE improved lipid profile, liver and kidney functions, immune response towards the emerging bacterial diseases. Besides this, feeding the fishes on diets supplemented with Moringa LE at concentration 0.25% kg−1 showed the best growth performance, and improved immunity. Moreover, it exhibited the highest protection against bacterial infection with Aeromonas hydrophila achieving the lowest mortality rate of 10% as compared to 80% of mortality rate at the control group.

Organic farming is an advantageous agricultural system that enhances agro-ecosystem health, including biogeochemical cycles, biological activity and biodiversity in soils. In this regard, greenhouse and lyzemeter experiments were conducted to evaluate eight compost preparations, and to investigate the combined effect of compost- Azotobacter chroococcum on growth and yield of wheat (Triticum aestivum L.) Cv. Misr 2 under different nitrogen levels (36, 72 and 108 kg N ha-1). In greenhouse experiment, application of compost treatment No. 8 (produced by mixture of rice straw, cattle dung and inoculated with Bacillus licheniformis and Bacillus sonorensis) attained the highest vegetative growth parameters at 46.3 cm plant height, 8.92 g plant fresh weight and 2.96 g dry weight of wheat plants at 30 days after sowing comparing with control. An increase of 100 % N2 treatment has been measured for all vegetative growth parameters at 60 and 90 days after sowing. Similar trend was also exhibited in N % of root and shoot of plant. On the other hand, significant enhancement in vegetative growth was obtained using co-amendments treatments with compost treatment No.8, mineral N2 and inoculation with Azotobacter chroococcum at different doses compared to traditional N-fertilizer dose for lyzemeter experiment. The data showed that application with 50% of full dose of compost supplemented with Azotobacter chroococcum is the most effective treatment for enhancing urease and dehydrogenase and microbial activity in soil, as well as yield parameters of plant at different period times compared to control.

A 205 samples representing eight different infant foods with various based materials were collected and analyzed for their microbiological properties. The contamination rate by aerobic spore formers was achieved 100% in milk based infant food with fruit, vegetables, honey, rice and infant milk powder. While, it was detected in 95, 60 and 65% of the infant food with wheat milk based, ready to use (infant food with fruit) and ready to use (infant food with vegetables), respectively. Biochemical Identification and API 50 CHB used to identify the obtained isolates and revealed that B. subtilis was the most frequently occurring Bacillus spp. Followed by B. licheniformis and B. circulans. While B. cereus was detected in 10.20% of the total isolates. Moreover, B. cereus was confirmed in 21.2% of milk based fruit, vegetables (15.7%), honey (17.2%), rice (14.1%) and wheat (12%) and vanished in the infant milk powder samples. Although, B. cereus noted in lower percentage but this strain is considered as the more harmful one in lower numbers. For that, the following part is focused on B. cereus. Forty five isolates obtained from B. Cereus contaminating samples were screened for prevalence of 3 important virulent enterotoxigenic genes using PCR technique. The CYTK gene had the highest presence which detected in 43 isolates (95.5%), followed by NHEC gene detected in 32 isolates. However, the HBLA gene was detected in just 5 isolates. So, many processes should be applied for controlling of pathogens to preserve infant lives. Keywords: Bacillus spp., Infant foods, Enterotoxigenic genes, Molecular detection

This study was undertaken to improve nutritional values and digestibility of water-hyacinth by solid-state fermentation with a white rot fungi, Pleurotus sajor-caju. At the end of 56 days fermentation of CaCO3 treated water-hyacinth, significant (p

Enterococcus faecium QU 50, a novel thermophilic L-lactic acid (LA) producing strain, was used in this study to ferment sugar mixtures into LA. Under the optimal fermentation conditions (50 °C, pH 6.5), strain QU 50 could ferment both mixed glucose/xylose sugars with relaxed CCR and mixed cellobiose/xylose sugars simultaneously without CCR to produce homo L-LA. The activity of enzymes related to xylose metabolism was also investigated. In the cells grown in a medium containing cellobiose/xylose, the activity of xylose isomerase and xylulose kinase, was 3.22 and 1.91 times higher, respectively, as compared to that of cells grown in a glucose/xylose medium. Strain QU 50 produced 70.8 g L−1 of L-LA with a yield of 1.04 g g−1 and a productivity of 2.95 g L−1 h−1 from simulated energy cane hydrolysate in batch fermentation. Immobilisation of strain QU 50 improved the operational stability of open repeated fermentation (three cycles), resulting in 61.1–64.3 g L−1 of L-LA with a yield of 1.01–1.02 g g−1 and a productivity of 3.22–3.82 g L−1 h−1. Thus, an efficient and cost-effective fermentation system was successfully established for L-LA production from sugar mixtures.

Herein, we report the complete genome sequence of Enterococcus faecium QU50, isolated from Egyptian soil and exhibiting intermediate susceptibility to vancomycin. The genome contains a 2,535,796-bp circular chromosome and two plasmids of 196,595 bp and 17,267 bp., Herein, we report the complete genome sequence of Enterococcus faecium QU50, isolated from Egyptian soil and exhibiting intermediate susceptibility to vancomycin. The genome contains a 2,535,796-bp circular chromosome and two plasmids of 196,595 bp and 17,267 bp. IS1062-like sequences were not found.

Optically pure lactic acid (LA) is an important chemical platform that has a wide range of industrial and biotechnological applications. Improved parameters for cost effective LA production are of great interest for industrial developments. In the present study, an alkaliphilic lactic acid bacterium, BoM 1-2, was selected among 369 newly obtained bacterial isolates. It was characterized using API 50 CHL kit and identified asEnterococcus hiraeBoM 1-2 by 16S rRNA gene sequence analysis. Efficient polymer-gradeL-lactic acid production was achieved at pH 9.0 and 40°C. In batch fermentation strategy using 20 g L−1glucose, 19.6 g L−1lactic acid was obtained with volumetric productivity of 2.18 g L−1 h−1. While using 100 g L−1glucose, 96.0 g L−1lactic acid was obtained with volumetric productivity of 1.07 g L−1 h−1.The highest lactic acid concentration of 180.6 g L−1was achieved in multipulse fed batch strategy with volumetric productivity of 0.65 g L−1 h−1. To achieve higher productivity, repeated fermentation processes were applied using the two different strategies. In the first strategy, the lactic acid productivity was increased from 1.97 g L−1 h−1to 4.48 g L−1 h−1when the total of 10 repeated runs were carried out using 60 g L−1glucose, but lactic acid productivity decreased to 2.95 g L−1 h−1using 100 g L−1glucose. In second strategy, repeated fermentation coupled with gradual increase in glucose concentration from 40 to 100 g L−1was conducted for 24 runs. A dramatic increase in LA productivity up to 39.9 g L−1 h−1(18-fold compared to first run) was achieved using 40 g L−1glucose while volumetric productivity ranging between 24.8 and 29.9 g L−1 h−1was achieved using 60–100 g L−1glucose.

Lignocellulosic and algal biomass are promising substrates for lactic acid (LA) production. However, lack of xylose utilization and/or sequential utilization of mixed-sugars (carbon catabolite repression, CCR) from biomass hydrolysates by most microorganisms limits achievable titers, yields, and productivities for economical industry-scale production. This study aimed to design lignocellulose-derived substrates for efficient LA production by a thermophilic, xylose-utilizing, and inhibitor-resistant Bacillus coagulans Azu-10. This strain produced 102.2 g/L of LA from 104 g/L xylose at a yield of 1.0 g/g and productivity of 3.18 g/L/h. The CCR effect and LA production were investigated using different mixtures of glucose (G), cellobiose (C), and/or xylose (X). Strain Azu-10 has efficiently co-utilized GX and CX mixture without CCR; however, total substrate concentration (>75 g/L) was the only limiting factor. The strain completely consumed GX and CX mixture and homoferemnatively produced LA up to 76.9 g/L. On the other hand, fermentation with GC mixture exhibited obvious CCR where both glucose concentration (>25 g/L) and total sugar concentration (>50 g/L) were the limiting factors. A maximum LA production of 50.3 g/L was produced from GC mixture with a yield of 0.93 g/g and productivity of 2.09 g/L/h. Batch fermentation of GCX mixture achieved a maximum LA concentration of 62.7 g/L at LA yield of 0.962 g/g and productivity of 1.3 g/L/h. Fermentation of GX and CX mixture was the best biomass for LA production. Fed-batch fermentation with GX mixture achieved LA production of 83.6 g/L at a yield of 0.895 g/g and productivity of 1.39 g/L/h.

Different fermentation strategies were investigated for improving lactic acid (LA) production by homofermentative LA-producing strain, Enterococcus hirae ds10. Batch mode with initial sugar molasses of 69.53 g/L achieved LA production of 36.79 g/L with a yield of 0.91 g/g and productivity of 1.02 g/L/h; however, 52% of sugar molasses was only consumed. Otherwise, in batch mode with high cell density (HCD), strain ds10 consumed more substrate achieving LA production at 49.49 g/L at yield (0.91 g/g) and low LA productivity (0.41 g/L/h). Subsequently, one-pulse and multi-pulse fed-batch strategies with/without HCD were provided better sugar utilization and higher LA production but low LA productivity was obtained. Interestingly, the repeated batch fermentation was conducted for 16 runs and achieved the highest LA of 61.76 g/L after 30 h at a higher initial sugar concentration of 85.87 g/L with an improvement of LA productivity at 2.06 g/L/h and yield at 0. 97 g/g.

Introduction/Objective On behalf of the diagnostic Medical Laboratory rapid, and accurate identification of bacteria with their one-to-one anti-microbial susceptibility outlines is of ultimate importance for the management of infected patients. Contemporary microbial identification methods employed in routine clinical diagnostic laboratories relies on the use of conventional phenotypic methods. Phenotypic methods are time consuming with minimum turn-around times of at least 24 hrs and in many occurrences of 48hrs. With the intention of accelerate laboratory processes the MALDI-TOF MS was familiarized. MALDI-TOF MS is established on proteomic profiling and permits for rapid identification of bacteria. This technology has not been widely used in Egypt, but has been regularly used in Europe for the past few years. Methods Two hundred forty three positive non duplicate blood cultures were accrued over a period of six months. Experimental aliquots were taken from excess sample material that was collected as part of routine clinical care. 105 were positive for Gram negative bacilli, 123 were positive for Gram positive cocci, 3 positive for Gram positive bacilli, and 7 were positive for yeast. MALDI-TOF identification was compared to conventional identification. Conventional identification consisted of a combination of MALDI-TOF identification of a subcultures colony by direct smear, biochemical reactions, Vitek 2, and molecular identification. Results Ninety seven of the one hundred and five blood cultures positive for Gram negative bacilli were monomicrobial. The majority of these were identified as Escherichia coli by conventional methods, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa. Eighty-four of these monomicrobial cultures were identified by MALDI-TOF to the species level. Eighty-one of the eighty-four were concordant with the conventional identification (96.4%). Conclusion The MALDI-TOF proved to be useful for the rapid and reliable identification of g-ve bacteria from the clinical specimens. The difference in turnaround time for bacterial identification was significant between MALDI-TOF MS and VITEK 2 with minimal preparation for the blood cultures.

The main objective of this study is to investigate the potentiality of cellulase producing isolates, Bacillus licheniformis 1-1v and Bacillus sonorensis 7-1v, as microbial additives on composting of rice straw materials. Different pyramid shape piles were constructed, and each contained 80 kg of rice straw and 288 kg of cattle manure, with/without 5 kg of feldspar supplementation (0.75%, w/w ). C / N ratio was adjusted to 35.8 before microbial inoculation. The piles were inoculated with either single strain or mixed cultures. The physical, chemical and biological parameters indicating the decomposition of organic material, maturation and quality of the compost product were investigated during the composting process. A rapid increase in compost temperature was obtained in inoculated piles. Moreover, piles containing mixed inoculants exhibited longer time at high temperatures >55 °C for 15 consecutive days compared to control treatments that lasted for only 5 consecutive days. The microbial inoculation had greatly reduced the composting time by 40–43% (from 89–96 days to 51–58 days). Additionally, it resulted in a higher decrease in the total organic carbon and carbon-to-nitrogen ratio, as well as increase in compost quality by an increase in total nitrogen, phosphorus, and potassium content. The analysis of moisture content, bulk density, pH value, electrical conductivity, phytotoxicity, and pathogenic bacterial content of the final compost products exhibited maturation and good quality of final product to be used without any limitations.

A few strains of lactic acid bacteria metabolise xylose into optically pure L-lactic acid (LA). This study achieved an effective homofermentative cell recycle continuous fermentation of xylose to L-LA with high concentration, productivity, and yield using Enterococcus mundtii QU 25. In conventional continuous fermentation, the optimal xylose concentration in the feeding solution is 50 g L−1, and the optimal dilution rate is 0.15 h−1. Continuous fermentation with cell recycling using a microfiltration membrane module produced an L-LA concentration of 32.3 g L−1 with a yield of 0.789 g g−1 and a productivity of 5.33 g L−1 h−1. Controlling pH and optimising the feeding medium were important for achieving a high L-LA yield with strain QU 25. Using corn steep liquor-containing medium at pH 6.2, a maximum L-LA concentration, yield and productivity were achieved at 41.0 g L−1, 1.01 g g−1, and 6.15 g L−1 h−1, respectively. This study is the first to report on continuous fermentation with cell recycling for lactic acid production from xylose.

Dynamic simulation of continuous mixed sugar fermentation with increasing cell retention time for lactic acid production using Enterococcus mundtiiQU 25

Production of optically pure lactic acid from lignocellulosic material for commercial purposes is hampered by several difficulties, including heterofermentation of pentose sugars and high energy consumption by mesophilic lactic acid bacteria. Here, we report a novel lactic acid bacterium, strain QU 50, that has the potential to produce optically pure l-lactic acid (≥99.2%) in a homofermentative manner from xylose under thermophilic conditions. Strain QU 50 was isolated from Egyptian fertile soil and identified as Enterococcus faecium QU 50 by analyzing its sugar fermentation pattern and 16S rRNA gene sequence. Enterococcus faecium QU 50 fermented xylose efficiently to produce lactic acid over wide pH (6.0-10.0) and temperature ranges (30-52°C), with a pH of 6.5 and temperature of 50°C being optimal. To our knowledge, this is the first report of homofermentative lactic acid production from xylose by a thermophilic lactic acid bacterium.

The use of lignocellulosic biomass for the production of optically pure lactic acid remains challenging because it requires efficient utilisation of mixed sugars without carbon catabolite repression (CCR). Enterococcus mundtii QU 25, a novel L-lactic acid-producing strain, was used in this study to ferment mixed sugars. This strain exhibited apparent CCR in a glucose–xylose mixture; however, replacement of glucose by cellobiose (cellobiose–xylose mixture) led to simultaneous consumption of both sugars without CCR. The production of lactic acid and activity of enzymes related to xylose metabolism were also investigated. Xylose isomerase and xylulokinase specific activity in cellobiose–xylose grown cells was three times higher than that in glucose–xylose grown cells. The addition of yeast extract and ammonium hydroxide effectively improved sugar utilisation and cell growth. Under the optimal conditions with simulated lignocellulosic hydrolysates, a high L-lactic acid concentration (up to 163 g L−1) was produced with a yield of 0.870 g g−1 and maximum productivity of 7.21 g L−1 h−1 without CCR in the fed-batch fermentation. Thus, we could establish rapid and simultaneous consumption of hexose and pentose sugars by using a lactic acid bacterium strain, which significantly increased production of high-purity L-lactic acid.

This study aimed to achieve effective lactic acid (LA) production from waste materials. From natural sources on banana peels-containing media, 253 bacterial isolates were obtained. Isolate FW26 was selected for LA production from untreated banana peels (no pre-treatment) at pH 9.0 and 50 °C. It was identified as Enterococcus faecium strain FW26 using 16S rRNA sequencing. The optimal solid-to-liquid ratio was 1:10 (w/v) achieving LA at 15.9 g L−1 from direct utilization of banana peels. Utilization of co-substrates achieved positive synergistic effects on growth and LA production. Fermentation of banana peels and food wastes mixture (1:1.5, w/w) exhibited 22.2% improvements in LA concentration. Besides, exclusion of medium components achieved comparable LA fermentation parameters to that obtained with nutrient supplementation. Moreover, controlling of fermentation pH exhibited 81% improvements in LA concentration achieving 33.3 ± 2.6 g L−1 with yield of 0.84 g g−1-consumed sugars. This indicate the potentiality of strain FW26 for LA production by direct utilization of untreated mixed wastes without nutrient supplementation under thermo-alkaline conditions.