The Utilization of Chicken Egg White Waste-Modified Nanofiber Membrane for Anionic Dye Removal in Batch and Flow Systems: Comprehensive Investigations into Equilibrium, Kinetics, and Breakthrough Curve.

This study investigated the use of chicken egg white (CEW) waste immobilized on weak acidic nanofiber membranes for removing the anionic acid orange 7 (AO7) dye in batch and continuous flow modes. Different experiments were conducted to evaluate the effectiveness of CEW-modified nanofiber membranes for AO7 removal, focusing on CEW immobilization conditions, adsorption kinetics, and thermodynamics. The CEW-modified nanofiber membrane (namely NM-COOH-CEW) exhibited a maximum AO7 adsorption capacity of 589.11 mg/g within approximately 30 min. The Freundlich isotherm model best represented the equilibrium adsorption data, while the adsorption kinetics followed a pseudo-second-order rate model. Breakthrough curve analysis using the Thomas model and the bed depth service time (BDST) model showed that the BDST model accurately described the curve, with an error percentage under 5%. To investigate AO7 elution efficiency, different concentrations of organic solvents or salts were tested as eluents. The NM-COOH-CEW nanofiber membrane exhibited promising performance as an effective adsorbent for removing AO7 dye from contaminated water.

Recent advances and challenges in sustainable management of plastic waste using biodegradation approach.

Versatility and desirable attributes of synthetic plastics have greatly contributed towards their wide applications. However, vast accumulation of plastic wastes in environment as a result of their highly recalcitrant nature has given rise to plastic pollution. Existing strategies in alleviating plastic wastes accumulation are inadequate, and there is a pressing need for alternative sustainable approaches in tackling plastic pollution. In this context, plastic biodegradation has emerged as a sustainable and environmental-friendly approach in handling plastic wastes accumulation, due to its milder and less energy-intensive conditions. In recent years, extensive research effort has focused on the identification of microorganisms and enzymes with plastic-degrading abilities. This review aims to provide a timely and holistic view on the current status of plastic biodegradation, focusing on recent breakthroughs and discoveries in this field. Furthermore, current challenges associated to plastic biodegradation are discussed, and the future perspectives for continuous advancement of plastic biodegradation are highlighted.

Cordyceps militaris Reduces Oxidative Stress and Regulates Immune T Cells to Inhibit Metastatic Melanoma Invasion.

In this study, the water extract of Cordyceps militaris (Linn.) Link (CM) was used as a functional material to investigate the inhibitory mechanisms on B16F10 and lung metastatic melanoma (LMM) cells. Reducing power, chelating ability, and 2,2-diphenyl-2-picrylhydrazyl (DPPH) assays were applied for antioxidative capacities, and we obtained positive results from the proper concentrations of CM. To examine the ability of CM in melanoma proliferation inhibition and to substantiate the previous outcomes, three cellular experiments were performed via (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT, a tetrazole) assay, cell migration, and invasion evaluation. The addition of CM to the incubation medium increased the number of CD8+ T cells significantly, which improved the immunogenicity. This study showed that CM exhibits various biological capabilities, including antioxidation, anti-tumor, tumor invasion suppression, and T cytotoxic cell activity promotion.

Biomass and lipid production by Rhodococcus opacus PD630 in molasses-based media with and without osmotic-stress.

Rhodococcus opacus PD630 was used to produce biomass and lipids in molasses-based media with and without osmotic stress. In a 7-day aerobic batch culture at 30 °C, the biomass and lipid concentrations were maximized using an initial molasses concentration of 80 g/L and ammonium acetate (nitrogen source) concentration of 2.14 g/L. At a fixed initial molasses concentration of 80 g/L, the concentration of the nitrogen source was further fine-tuned to 2.25 g/L, to maximize the lipid content of the biomass to around 30% by dry mass. This medium was used to test the effects of stressing salts (sodium acetate, magnesium sulfate, sodium chloride) on production of lipids and biomass. A two-step bolus feeding with magnesium sulfate and sodium acetate, enhanced the final biomass concentration to around 19 g/L (a 50% increase relative to control), but the lipid content in the biomass was reduced to around 16% w/w. A 33% enhancement in lipid concentration relative to control, was achieved by feeding magnesium sulfate and sodium acetate. Sugarcane molasses could be effectively used to produce biomass and lipids instead of using the much more expensive pure carbon sources such as glucose and sucrose.

Cellulosic ethanol production: Progress, challenges and strategies for solutions.

Lignocellulosic biomass is a sustainable feedstock for fuel ethanol production, but it is characterized by low mass and energy densities, and distributed production with relatively small scales is more suitable for cellulosic ethanol, which can better balance cost for the feedstock logistics. Lignocellulosic biomass is recalcitrant to degradation, and pretreatment is needed, but more efficient pretreatment technologies should be developed based on an in-depth understanding of its biosynthesis and regulation for engineering plant cell walls with less recalcitrance. Simultaneous saccharification and co-fermentation has been developed for cellulosic ethanol production, but the concept has been mistakenly defined, since the saccharification and co-fermentation are by no means simultaneous. Lignin is unreactive, which not only occupies reactor spaces during the enzymatic hydrolysis of the cellulose component and ethanol fermentation thereafter, but also requires extra mixing, making high solid loading difficult for lignocellulosic biomass and ethanol titers substantially compromised, which consequently increases energy consumption for ethanol distillation and stillage discharge, presenting another challenge for cellulosic ethanol production. Pentose sugars released from the hydrolysis of hemicelluloses are not fermentable with Saccharomyces cerevisiae used for ethanol production from sugar- and starch-based feedstocks, and engineering the brewing yeast and other ethanologenic species such as Zymomonas mobilis with pentose metabolism has been performed within the past decades. However strategies for the simultaneous co-fermentation of pentose and hexose sugars that have been pursued overwhelmingly for strain development might be modified for robust ethanol production. Finally, unit integration and system optimization are needed to maximize economic and environmental benefits for cellulosic ethanol production. In this article, we critically reviewed updated progress, and highlighted challenges and strategies for solutions.

Production of carotenoids and lipids by Rhodococcus opacus PD630 in batch and fed-batch culture.

Production of carotenoids by Rhodococcus opacus PD630 is reported. A modified mineral salt medium formulated with glycerol as an inexpensive carbon source was used for the fermentation. Ammonium acetate was the nitrogen source. A dry cell mass concentration of nearly 5.4 g/L could be produced in shake flasks with a carotenoid concentration of 0.54 mg/L. In batch culture in a 5 L bioreactor, without pH control, the maximum dry biomass concentration was ~30 % lower than in shake flasks and the carotenoids concentration was 0.09 mg/L. Both the biomass concentration and the carotenoids concentration could be raised using a fed-batch operation with a feed mixture of ammonium acetate and acetic acid. With this strategy, the final biomass concentration was 8.2 g/L and the carotenoids concentration was 0.20 mg/L in a 10-day fermentation. A control of pH proved to be unnecessary for maximizing the production of carotenoids in this fermentation.

Editorial: Bioprocess beyond the large scale production.

Advances in bioprocess engineering continue to step forward in its own field of large scale production in mid- and down-stream processes of biotechnology. Some of the recent researches are shown in this AFOB (Asian Federation of Biotechnology) Special issue of Advances in Bioprocess Engineering.

Production of ethanol from sweet sorghum juice using VHG technology: a simulation case study.

The aims of this study were to develop the kinetic model and determine kinetic parameters describing ethanol production from sweet sorghum juice using very high gravity technology in the batch fermentation of Saccharomyces cerevisiae NP01. The obtained experimental data were tested with four different types of model, based on the experimental data, accounting for the substrate limitation, substrate inhibition, product inhibition, and the combination of those three effects, respectively. The optimization technique to find kinetic parameters was non-linear regression using Marquardt method performed through numerical procedure. The chosen model with its kinetic parameters obtained in the batch mode was validated and tested against the other independent experimental data in the small batch-scale and large-scale fermenter, in order to investigate the applicability and scale-up effect of the model, respectively. Then, the obtained model with its parameters was applied in the simulations of the continuous and fed-batch operations to examine the concentration profiles of fermentation components with the variations in operating parameters such as the dilution rate, feed-flow rate, start-up time, and feed concentration. The results indicated that the kinetic model (the substrate limitation with substrate and product inhibition effects) was suitable to describe ethanol fermentation. In the continuous mode, using the dilution rate of 0.01 h(-1), the maximum ethanol concentration obtained was, approximately, 90 g/l whereas the simulated results from the fed-batch operation revealed that the maximum ethanol concentration at quasi-steady state condition was, approximately, 96 g/l. The start-up time of 21 h was the fastest time to reach the steady-state and quasi-steady state for both the continuous and fed-batch modes, respectively.

Ethanol production from sweet sorghum juice under very high gravity conditions: batch, repeated-batch and scale up fermentation

Batch ethanol fermentations from sweet sorghum juice by Saccharomyces cerevisiae NP 01 were carried out in a 500 ml air-locked Erlenmeyer flask under very high gravity (VHG) and static conditions. The maximum ethanol production efficiency was obtained when 9 g l-1 of yeast extract was supplemented to the juice. The ethanol concentration (P), productivity (Qp) and yield (Yp/s) were 120.24 +/- 1.35 g l-1, 3.01 +/- 0.08 g l-1 h-1 and 0.49 +/- 0.01, respectively. Scale up ethanol fermentation in a 5-litre bioreactor at an agitation rate of 100 rev min-1 revealed that P, Qp and Yp/s were 139.51 +/- 0.11 g l-1, 3.49 +/- 0.00 g l-1 h-1 and 0.49 +/- 0.01, respectively, whereas lower P (119.53 +/- 0.20 g l-1) and Qp (2.13 +/- 0.01 g l-1 h-1) were obtained in a 50-litre bioreactor. In the repeated-batch fermentation in the 5-litre bioreactor with fill and drain volume of 50 percent of the working volume, lower P and Qp were observed in the subsequent batches. P in batch 2 to 8 ranged from 103.37 +/- 0.28 to 109.53 +/- 1.06 g l-1.

Production of L-phenylalanine from glycerol by a recombinant Escherichia coli.

The production of L-phenylalanine is conventionally carried out by fermentations that use glucose or sucrose as the carbon source. This work reports on the use of glycerol as an inexpensive and abundant sole carbon source for producing L-phenylalanine using the genetically modified bacterium Escherichia coli BL21(DE3). Fermentations were carried out at 37 degrees C, pH 7.4, using a defined medium in a stirred tank bioreactor at various intensities of impeller agitation speeds (300-500 rpm corresponding to 0.97-1.62 m s(-1) impeller tip speed) and aeration rates (2-8 L min(-1), or 1-4 vvm). This highly aerobic fermentation required a good supply of oxygen, but intense agitation (impeller tip speed approximately 1.62 m s(-1)) reduced the biomass and L-phenylalanine productivity, possibly because of shear sensitivity of the recombinant bacterium. Production of L-phenylalanine was apparently strongly associated with growth. Under the best operating conditions (1.30 m s(-1) impeller tip speed, 4 vvm aeration rate), the yield of L-phenylalanine on glycerol was 0.58 g g(-1), or more than twice the best yield attainable on sucrose (0.25 g g(-1)). In the best case, the peak concentration of L-phenylalanine was 5.6 g L(-1), or comparable to values attained in batch fermentations that use glucose or sucrose. The use of glycerol for the commercial production of L-phenylalanine with E. coli BL21(DE3) has the potential to substantially reduce the cost of production compared to sucrose- and glucose-based fermentations.

Ethanol production from sweet sorghum juice using very high gravity technology: effects of carbon and nitrogen supplementations.

Ethanol production from sweet sorghum juice by Saccharomyces cerevisiae NP01 was investigated under very high gravity (VHG) fermentation and various carbon adjuncts and nitrogen sources. When sucrose was used as an adjunct, the sweet sorghum juice containing total sugar of 280 g l(-1), 3 g yeast extract l(-1) and 5 g peptone l(-1) gave the maximum ethanol production efficiency with concentration, productivity and yield of 120.68+/-0.54 g l(-1), 2.01+/-0.01 g l(-1) h(-1) and 0.51+/-0.00 g g(-1), respectively. When sugarcane molasses was used as an adjunct, the juice under the same conditions gave the maximum ethanol concentration, productivity and yield with the values of 109.34+/-0.78 g l(-1), 1.52+/-0.01 g l(-1) h(-1) and 0.45+/-0.01 g g(-1), respectively. In addition, ammonium sulphate was not suitable for use as a nitrogen supplement in the sweet sorghum juice for ethanol production since it caused the reduction in ethanol concentration and yield for approximately 14% when compared to those of the unsupplemented juices.

A model of xylitol production by the yeast Candida mogii.

Production of xylitol from xylose in batch fermentations of Candida mogii ATCC 18364 is discussed in the presence of glucose as the cosubstrate. Various initial ratios of glucose and xylose concentrations are assessed for their impact on yield and rate of production of xylitol. Supplementation with glucose at the beginning of the fermentation increased the specific growth rate, biomass yield and volumetric productivity of xylitol compared with fermentation that used xylose as the sole carbon source. A mathematical model is developed for eventual use in predicting the product formation rate and yield. The model parameters were estimated from experimental observations, using a genetic algorithm. Batch fermentations, which were carried out with xylose alone and a mixture of xylose and glucose, were used to validate the model. The model fitted well with the experimental data of cell growth, substrate consumption and xylitol production.