Search

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Detailed knowledge of the flow characteristics, bubble movement, and mass transfer is a prerequisite for the proper design of multiphase bioreactors. Often, mechanistic spatiotemporal models and computational fluid dynamics, which intrinsically require computationally demanding analysis of local interfacial forces, are applied. Typically, such approaches use volumetric mass-transfer coefficient (kLa) models, which have demonstrated their predictive power in water systems. However, are the related results transferrable to multiphase fermentations with different physicochemical properties? This is crucial for the proper design of biotechnological processes. Accordingly, this study investigated a given set of mass transfer data to characterize the fermentation conditions. To prevent time-consuming simulations, computational efforts were reduced using a force balance stationary 0-dimension model. Therefore, a competing set of drag models covering different mechanistic assumptions could be evaluated. The simplified approach of disregarding fluid movement provided reliable results and outlined the need to identify the liquid diffusion coefficients in fermentation media. To predict the rising bubble velocities uB, the models considering the Morton number (Mo) showed superiority. The mass transfer coefficient kL was best described using the well-known Higbie approach. Taken together, the gas hold-up, specific surface area, and integral mass transfer could be accurately predicted. [ABSTRACT FROM AUTHOR]

Previous research has indicated that Pseudomonas aurantiaca ST-TJ4 possesses a notable antagonistic impact on Phytophthora cinnamomi and holds promising potential for biocontrol. In this study, a combination of a single-factor experiment, a Plackett–Burman design and a response surface approach was employed to investigate the optimal formula of ST-TJ4 fermentation medium. Furthermore, the stability of ST-TJ4 fermentation filtrate and its biocontrol effect on Ph. cinnamomi in vivo were also evaluated. The results revealed that the optimal culture conditions for ST-TJ4 involved the use of 20.59 g/L of glucose and 18.76 g/L of yeast extract powder. Following optimization, the fermentation filtrate of ST-TJ4 exhibited an inhibition rate of 76.5%, representing a 15% increase compared to previous levels. Additionally, phzA, phzB, phzD, phzE, phzF and phzO genes involved in the synthesis of phenazine-1-carboxylic acid (PCA) and 2-hydroxyphenazine (2-OH-PHZ) were also upregulated. The ST-TJ4 fermentation filtrate demonstrated strong alkali resistance, weak acid resistance and favorable temperature and UV light stability. Furthermore, in vitro inoculation experiments confirmed that optimizing the fermentation medium reduced Ps. cinnamomi's ability to infect the leaves of Rhododendron pulchrum. [ABSTRACT FROM AUTHOR]

Introduction: Adding a fermentation medium is an effective way to improve the quality of cigar tobacco leaves. Methods: A novel microbial fermentation medium produced by an edible medicinal fungus, Tremella aurantialba SCT-F3 (CGMCC No.23831) was used to improve the quality of cigar filler leaves (CFLs). Changes in sensory quality, chemical components, volatile flavor compounds (VFCs), and the structure and function of microbes were investigated during the fermentation process. Results: The sensory quality of CFLs supplemented with the T. aurantialba SCT-F3 fermentation medium significantly improved. Adding the fermentation medium increased the total alkaloid, reducing sugar, total sugar, and 12 VFCs significantly. A total of 31 microbial genera were significantly enriched, which increased the microbial community's richness and diversity. Microbial functions increased, including nucleotide biosynthesis, amino acid biosynthesis, fatty acid and lipid biosynthesis, nicotine degradation, and nicotinate degradation. During fermentation, the total alkaloid, reducing sugar, and total sugar content decreased. The richness and diversity of the microbial community decreased, whereas bacterial enzyme activity increased. At the end of fermentation, the sensory quality was excellent. The microbial structure gradually stabilized, and functional genes were low. The contents of the four Maillard reaction products and three nicotine degradation products increased significantly. 2-Ethyl-6-methylpyrazine, methylpyrazine, D,L-anatabine, β-nicotyrine, nicotinic degradation products, and total nitrogen were significantly and positively correlated with sensory quality. Methylpyrazine, D,L-anatabine, and β-nicotyrine were negatively correlated with Luteimonas, Mitochondria, Paracoccus, Stemphylium, and Stenotrophomonas. Conclusion: This research provides not only a new microbial fermentation medium that utilizes edible and medicinal fungi to improve the quality of fermented CFLs, but also new ideas for the development and application of other edible medicinal fungi to improve the quality of cigar tobacco leaves. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bacillus subtilis spores have important biological applications; however, high spore-cell densities and sporulation efficiencies in fermentation is poorly reported. This study systematically analyzed the spore densities and formation efficiency of B. subtilis BSNK-5 in different culture substrates. A response surface regression equation was established based on the results of single factor and Box–Behnken experimental designs. The optimal medium formulation, as predicted from the equation, consisted of soluble starch at 3 g·L−1, soybean flour at 12 g·L−1, and MgSO4 at 5 g·L−1. The spore yield reached 2.43 × 109 CFU·mL−1, and the sporulation rate was 83.3%, which was nearly three times higher than before optimization using an optimized medium at 36 °C and 200 rpm for 60 h. [ABSTRACT FROM AUTHOR]

The liquid-state fermentation medium conditions of Trichoderma reesei of high yield cellulase were optimized with natural agricultural products as the main raw materials by different test design methods, such as the Plackett-Burman (PB), steepest climbing, Box-Behnken (BB) and response surface method (RSM) analysis. The results showed that the optimal fermentation medium conditions for enzyme production were soybean meal 2.140%, wheat bran 1.88%, peptone 0.30%. Under these conditions, the cellulase activity of the fermentation broth could reach (42.62±1.30) U/mL. In the later stage of fermentation (5 d), with the large growth of mycelium, the cellulase activity increased continuously. The crude enzyme solution could degrade cellulose and hemicellulose in corn straw to produce fermentable sugars such as free glucose, xylose, arabinose and cellobiose. [ABSTRACT FROM AUTHOR]

Objective: This study was conducted to enhance the production of tacrolimus in Streptomyces tsukubaensis by strain mutagenesis and optimization of the fermentation medium. Results: A high tacrolimus producing strain S. tsukubaensis FIM-16-06 was obtained by ultraviolet mutagenesis coupled with atmospheric and room temperature plasma mutagenesis.Then, nine variables were screened using Plackett–Burman experimental design, in which soluble starch, peptone and Tween 80 showed significantly affected tacrolimus production. Further studies were carried out employing central composite design to elucidate the mutual interaction between the variables and to work out optimal fermentation medium composition for tacrolimus production. The optimum fermentation medium was found to contain 61.61 g/L of soluble starch, 20.61 g/L of peptone and 30.79 g/L of Tween 80. In the optimized medium, the production of tacrolimus reached 1293 mg/L in shake-flask culture, and reached 1522 mg/L while the scaled-up fermentation was conducted in a 1000 L fermenter, which was about 3.7 times higher than that in the original medium. Conclusions: Combining compound mutation with rational medium optimization is an effective approach for improving tacrolimus production, and the optimized fermentation medium could be efficiently used for industrial production. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the production of biological preparations for agriculture there are promising jet bioreactors with an external circulation ring, providing intense mixing of the medium along with a high degree of aeration. However, application of these bioreactors is limited by large shear loads on the microorganisms (microorganism cells) arising in the circulation pump. The article deals with one of the ways for solving this problem by using a lowcapacity pump for the circulation of the fermentation medium according to a non-standard scheme of medium jet aeration in order to intensify the mass exchange processes. There are presented results of physical simulation of the mixing parameters of flows in an aerator-jet mixer and their impact upon the intensity of metabolic processes in the circulation ring of a bioreactor. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Poly‐ε‐L‐lysine is a natural homo‐polyamide of L‐lysine with excellent antimicrobial properties, which can be used as a novel preservative and has a wide range of applications. In this paper, the fermentation medium for ε‐PL production by Streptomyces diastatochromogenes 6#‐7 was optimized by Response Surface Methodology. The results of Plackett‐Burman design showed that glucose, yeast extract and (NH4)2SO4 were the major influencing factors in ε‐PL production of S. diastatochromogenes 6#‐7. The optimal concentrations of glucose, yeast extract and (NH4)2SO4 were determined to be 60, 7·5 and 7·5 g l−1 according to Box‐Behnken experiment and regression analysis, respectively. Under the optimized conditions, the ε‐PL yield in shake‐flask fermentation was 0·948 ± 0·030 g l−1, which was in good agreement with the predicted value of 0·970 g l−1. The yield was improved by 43·1% from that with the initial medium. In 5 l jar‐fermenter the ε‐PL yield reached 25·5 g l−1, which was increased by 56·4% from the original medium. In addition, the fermentation time was reduced from 174 to 120 h. Significance and Impact of the Study: Medium optimization is a very practical and valuable tool for fermentation industry to improve product yield and minimize by‐products as well as reduce overall manufacturing costs. The response surface methodology is not new, but it is still a very effective method in medium optimization research. This study used ε‐polylysine fermentation as an example to demonstrate how the product yield can be significantly increased by medium optimization through surface response methodology. Similar approach can be used in other microbial fermentations such as in pharmaceutical, food, agricultural and energy industries. As an example, ε‐polylysine is one of a few newly approved natural food‐grade antimicrobials for food and beverages preservations. Yield improvement is economically beneficial to not only ε‐polylysine manufacturers but also to their users and consumers due to lower costs and price. [ABSTRACT FROM AUTHOR]

Bacterial cellulose had been proven to be a very versatile natural polymer produced by bacteria. One of the major constraints in producing bacterial cellulose is the high cost of fermentation medium. This study examines the potential use of papaya juice as a lowcost fermentation medium for the production of bacterial cellulose. The fermentation of Acetobacter xylinum 0416 was carried out under static fermentation with an initial pH of 5.5, a temperature of 28±1°C and a fermentation period of 5 days using different juice extracted from ripe and unripe papaya. The highest production of bacterial cellulose was detected in ripe papaya pulp juice with a total weight of 35.37 g/l. Juice obtained from various parts of the fruit produced bacterial cellulose between 3.33 g/l and 16.10 g/l. By referring to the standard medium (Hestrin-Schramm (HS) medium), ripe papaya pulp juice shows the highest potential to be used as an alternative for the production of bacterial cellulose. This is due to its high glucose concentration that provide suitable conditions for A.xylinum 0416 to grow and produce bacterial cellulose. [ABSTRACT FROM AUTHOR]

The main purpose of this research was to optimize the production of urate oxidase through mutagenesis of Bacillus subtilis. The organism was subjected to ultra violet irradiation and chemical mutagenesis. The strain was chemically mutated by using ethyl methane sulfonate and ethidium bromide. 2- thiouric acid was used as a selective marker to identify the UV and chemically mutated Bacillus subtilis. Ethyl methane sulfonate treated B. subtilis (180 minutes dose) was proved to be the best for optimum production of urate oxidase by 3 log kill/survival curve. Fermentation medium was also optimized, it was found that substrate concentration (0.5%), fermentation period (36 h), pH (8.5), temperature (35°C), inoculum size (3%) enhanced the activity (42.77 ± 0.36 U/mL) of mutant derived enzyme. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, we have investigated the importance of fermentation media on grain formation and the microbial characteristics of sugary kefir. The sugary kefir grains were fermented in brown sugar, cow''s milk or goat''s milk. Using culture-dependent and culture-independent methods, we identified the microorganisms present in both the grains and filtrate and then evaluated their distribution. The structure of the grains was also observed by scanning electronic microscopy (SEM). The identification results indicated that there were remarkable changes in microbial ecological profiles of the sugary kefir grains and their filtrates when brown sugar and milk were compared as fermentation media. Three lactic acid bacteria (LAB) species (Leuconostoc mesenteroides, Lactobacillus mali and Lactobacillus hordei) were found in the grains fermented using brown sugar. However, four species, named Leu. mesenteroides, Lactococcus lactis, Bifidobacterium psychraerophilum and Enterococcus faecalis, were identified in the grains fermented using either cow''s or goat''s milk. The size and structure of the kefir grains were also significantly influenced by the culture medium. We hypothesize that the grains originally may contain many different microorganisms and the identified changes are an adaption to each specific medium during grain formation and growth. The distribution of strains thus may vary depending on the carbon and energy sources available for grain fermentation and these microbial changes will further affect the granulation and growth of the grains. This study is important to our understanding of the mechanism of kefir grain formation and growth because it explores the relationship between fermentation media and kefir microorganisms. [Copyright &y& Elsevier]

Fermentation of biomass derived synthesis gas to ethanol is a sustainable approach that can provide more usable energy and environmental benefits than food-based biofuels. The effects of various medium components on ethanol production by Clostridium ragsdalei utilizing syngas components (CO:CO) were investigated, and corn steep liquor (CSL) was used as an inexpensive nutrient source for ethanol production by C. ragsdalei. Elimination of Mg, NH and PO decreased ethanol production from 38 to 3.7, 23 and 5.93 mM, respectively. Eliminating Na, Ca, and K or increasing Ca, Mg, K, NH and PO concentrations had no effect on ethanol production. However, increased Na concentration (171 mM) inhibited growth and ethanol production. Yeast extract (0.5 g l) and trace metals were necessary for growth of C. ragsdalei. CSL alone did not support growth and ethanol production. Nutrients limiting in CSL were trace metals, NH and reducing agent (Cys: cysteine sulfide). Supplementation of trace metals, NH and CyS to CSL (20 g l, wet weight basis) yielded better growth and similar ethanol production as compared to control medium. Using 10 g l, the nutritional limitation led to reduced ethanol production. Higher concentrations of CSL (50 and 100 g l) were inhibitory for cell growth and ethanol production. The CSL could replace yeast extract, vitamins and minerals (excluding NH). The optimized CSL medium produced 120 and 50 mM of ethanol and acetate, respectively. The CSL could provide as an inexpensive source of most of the nutrients required for the syngas fermentation, and thus could improve the economics of ethanol production from biomass derived synthesis gas by C. ragsdalei. [ABSTRACT FROM AUTHOR]

Abstract: Aeration and agitation are important variables to ensure effective oxygen transfer rate during aerobic bioprocesses; therefore, the knowledge of the volumetric mass transfer coefficient (k L a) is required. In view of selecting the optimum oxygen requirements for extractive fermentation in aqueous two-phase system (ATPS), the k L a values in a typical ATPS medium were compared in this work with those in distilled water and in a simple fermentation medium, in the absence of biomass. Aeration and agitation were selected as the independent variables using a 22 full factorial design. Both variables showed statistically significant effects on k L a, and the highest values of this parameter in both media for simple fermentation (241s−1) and extractive fermentation with ATPS (70.3s−1) were observed at the highest levels of aeration (5vvm) and agitation (1200rpm). The k L a values were then used to establish mathematical correlations of this response as a function of the process variables. The exponents of the power number (N 3 D 2) and superficial gas velocity (V s) determined in distilled water (α =0.39 and β =0.47, respectively) were in reasonable agreement with the ones reported in the literature for several aqueous systems and close to those determined for a simple fermentation medium (α =0.38 and β =0.41). On the other hand, as expected by the increased viscosity in the presence of polyethylene glycol, their values were remarkably higher in a typical medium for extractive fermentation (α =0.50 and β =1.0). A reasonable agreement was found between the experimental data of k L a for the three selected systems and the values predicted by the theoretical models, under a wide range of operational conditions. [Copyright &y& Elsevier]

In the hope of developing a vaccine against Clostridium difficile based on its toxin(s), we have developed a fermentation medium for the bacterium that results in the formation of Toxin A and contains no meat or dairy products, thus obviating the problem of possible prion diseases. Particular preparations of hydrolyzed soy proteins, especially Soy Peptone A3, have been found to replace both the meat/dairy product tryptone in the preparation of working cell banks and seed media, and NZ-Soy BL4 does the same in the fermentation medium. These replacements yield even higher toxin titers. [ABSTRACT FROM AUTHOR]