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This study aimed to develop an eco-friendly flexible surface-enhanced Raman scattering (SERS) substrate for in-situ detection of pesticides using biodegradable bacterial nanocellulose (BNC). Plasmonic silver nanoparticle- bacterial nanocellulose paper (AgNP-BNCP) composites were prepared by vacuum-assisted filtration. After loading AgNPs into BNC hydrogel, AgNPs were trapped firmly in the network of nanofibrous BNCP upon ambient drying process, resulting in 3D SERS hotspots within a few-micron depth on the substrate. The fabricated AgNP-BNCPs exhibited high SERS activity with good reproducibility and stability as demonstrated by the detection of 4-aminothiophenol and methomyl pesticide. Due to the optical transparency of BNCP, a direct and rapid detection of methomyl on fruit peels using AgNP-BNCPs can be achieved, demonstrating a simple and effective 'paste-and-read' SERS approach. These results demonstrate potential of AgNP-BNCP composites for user-friendly in-situ SERS analysis.

Dental root canal treatment is required when dental caries progress to infection of the dental pulp. A major goal of this treatment is to provide complete decontamination of the dental root canal system. However, the morphology of dental root canal systems is complex, and many human dental roots have inaccessible areas. In addition, dental reinfection is fairly common. In conventional treatment, a cotton pellet and paper point made from plant cellulose is used to dry and sterilize the dental root canal. Such sterilization requires a treatment material with high absorbency to remove any residue, the ability to improve the efficacy of intracanal medication and high biocompatibility. Bacterial cellulose (BC) is produced by certain strains of bacteria. In this study, we developed BC in a pointed form and evaluated its applicability as a novel material for dental canal treatment with regard to solution absorption, expansion, tensile strength, drug release and biocompatibility. We found that BC has excellent material and biological characteristics compared with conventional materials, such as paper points (plant cellulose). BC showed noticeably higher absorption and expansion than paper points, and maintained a high tensile strength even when wet. The cumulative release of a model drug was significantly greater from BC than from paper points, and BC showed greater compatibility than paper points. Taken together, BC has great potential for use in dental root canal treatment.

Cellulose (in the form of printed paper) has always been the prime medium for displaying information in our society and is far better than the various existing display technologies. This is because of its high reflectivity, contrast, low cost and flexibility. There is a major initiative to push for a dynamic display technology that emulates paper (popularly known as "electronic paper"). We have successfully demonstrated the proof of the concept of developing a dynamic display on cellulose. To the best of our knowledge, this is the first significant effort to achieve an electronic display using bacterial cellulose. First, bacterial cellulose is synthesized in a culture of Acetobacter xylinum in standard glucose-rich medium. The bacterial cellulose membrane thus formed (not pulp) is dimensionally stable, has a paper-like appearance and has a unique microfibrillar nanostructure. The technique then involves first making the cellulose an electrically conducting (or semi-conducting) sheet by depositing ions around the microfibrils to provide conducting pathways and then immobilizing electrochromic dyes within the microstructure. The whole system is then cased between transparent electrodes, and upon application of switching potentials (2-5 V) a reversible color change can be demonstrated down to a standard pixel-sized area (ca. 100 microm2). Using a standard back-plane or in-plane drive circuit, a high-resolution dynamic display device using cellulose as substrate can be constructed. The major advantages of such a device are its high paper-like reflectivity, flexibility, contrast and biodegradability. The device has the potential to be extended to various applications, such as e-book tablets, e-newspapers, dynamic wall papers, rewritable maps and learning tools.

Suspended solids in the nutrient medium for Acetobacter xylinium in a rotating disk bioreactor become incorporated into the gelatinous mat of bacterial cellulose as it forms. Embedding fibers of ordinary cellulose creates composites with enhanced strength and the toughness of bacterial cellulose. Purified cellulose and elongated fibers from paper are incorporated differently than are spherical particles such as silica gel. About 90% of the final cellulose can come from scrap paper, and dried composite sheets were much stronger than plain bacterial cellulose per unit area.

In the beer brewing industry, microbial spoilage presents a consistent threat that must be monitored and controlled to ensure the palatability of a finished product. Many of the predominant beer spoilage microbes have been identified and characterized, but the mechanisms of contamination and persistence remain an open area of study. Post-production, many beers are distributed as kegs that are attached to draft delivery systems in retail settings where ample opportunities for microbial spoilage are present. As such, restaurants and bars can experience substantial costs and downtime for cleaning when beer draft lines become heavily contaminated. Spoilage monitoring on the retail side of the beer industry is often overlooked, yet this arena may represent one of the largest threats to the profitability of a beer if its flavor profile becomes substantially distorted. In this study, we sampled and cultured microbial communities found in beers dispensed from a retail draft system to identify the contaminating bacteria and yeasts. We also evaluated their capability to establish new biofilms in a controlled setting. Among four tested beer types, we identified over a hundred different contaminant bacteria and nearly twenty wild yeasts. The culturing experiments demonstrated that most of these microbes were viable and capable of joining new biofilm communities. From these data, we provide an important starting point for the efficient monitoring of beer spoilage in draft systems and provide suggestions for cleaning protocol improvements that can benefit the retail community.ImportanceBeer production, packaging, and service are each vulnerable to contamination by microbes that metabolize beer chemicals and impart undesirable flavors, which can result in the disposal of entire batches. Therefore, great effort is taken by brewmasters to reduce and monitor contamination during production and packaging. A commonly overlooked quality control stage of a beer supply chain is at the retail service end, where beer kegs supply draft lines in bars and restaurants under non-sterile conditions. We found that retail draft line contamination is rampant and that routine line cleaning methods are insufficient to efficiently suppress beer spoilage. Thus, many customers unknowingly experience spoiled versions of the beers they consume. This study identified the bacteria and yeast that were resident in draft beer samples and also assessed their abilities to colonize tubing material as members of stable biofilm communities.

Resumen Introducción. Las levaduras, las bacterias ácido lácticas y ácido acéticas, involucradas en la fermentación de cacao, son las responsables del consumo de los compuestos en la pulpa para desarrollar los precursores de sabor dentro del grano de cacao. Sin embargo, la fermentación es difícil de controlar por la complejidad de este proceso y las múltiples variables que la afectan, entre ellas la genética del cultivo. Objetivo. Analizar las transformaciones bioquímicas de diferentes grupos genéticos del cacao (Theobroma cacao L.) durante una micro fermentación controlada. Materiales y métodos. Se estableció una metodología de micro fermentación, con un cultivo iniciador de H. opuntiae y Acetobacter spp. en 4 grupos genéticos, obtenidos de clones comerciales del CATIE e híbridos de fincas de Upala. A lo largo de la fermentación se analizaron glucosa, fructosa, etanol, ácido láctico y acético en pulpa y metilxantinas (teobromina y cafeína) y (-)-epicatequina en grano. Resultados. No se encontraron diferencias significativas en el contenido y comportamiento de azúcares, ácidos orgánicos o etanol en pulpa a lo largo de la fermentación, pero sí en el tiempo de fermentación. Se observó una disminución de metilxantinas y epicatequinas, debido a reacciones enzimáticas y no enzimáticas. El contenido promedio de epicatequina resultó ser el compuesto distintivo entre los grupos genéticos del CATIE y cafeína en los cacaos comerciales. Conclusión. La metodología empleada posee un efecto regulador en el comportamiento de algunos metabolitos estudiados en pulpa de diferentes genéticas a lo largo de la fermentación, así como epicatequina y metilxantinas en grano. Abstract Introduction. Yeasts, lactic acid and acetic acid bacteria, involved in cocoa fermentation are responsible for consuming the compounds in the pulp to develop flavor precursors within the cocoa bean. However, cocoa fermentation is difficult to control due to the complexity of this process and the multiple variables that affect it, including the genetics of the crop. Objective. To analyze the biochemical transformations of different genetic groups of cocoa (Theobroma cacao L.) during a controlled micro-fermentation. Materials and methods. A micro-fermentation methodology was developed with a starter culture of H. opuntiae and Acetobacter spp. in 4 genetic groups, grown in the CATIE Clonal Garden and hybrids from different farms in the Upala area. Throughout the fermentation process glucose, fructose, ethanol, lactic acid and acetic acid were analyzed in pulp, and methylxanthines (theobromine and caffeine) and (-)-epicatechin in the bean. Results. No significant differences were found in the content and dynamics of sugars, organic acids and ethanol in pulp throughout the fermentation, but differences were found at fermentation time. A decrease in methylxanthines and epicatechin triggered by enzymatic and non-enzymatic reactions was observed. The average epicatechin content proved to be the distinctive compound between CATIE's genetic groups and caffeine in commercial cocoa. Conclusion. The methodology used had a regulatory effect on the behavior of some of the studied metabolites in pulp of different genetic throughout fermentation, as well as epicatechin and methylxanthines in the bean.

Many black water or feces and urine field observations in Tanjung Pinang City were dumped directly into the ditches, rivers, and sea. This proves that the management of domestic liquid waste in the City of Tanjungpinang, especially black water, has not yet received serious attention, resulting in a decline in environmental quality. One of the stages in processing black water is decomposition. The decomposition process can be assisted by bacteria, one of which is cellulose-degrading bacteria. This study aims to find bacterial isolates that have the potential to degrade cellulose in feces from coastal soils in Tanjung Pinang City. This research is a laboratory experimental research. The results of this study were obtained 16 bacterial isolates that can degrade cellulose. From these 16 isolates, 3 genera of bacteria were obtained, namely Pseudomonas, Acetobacter and Acinetobacter. Keywords: Cellulose Degradation Bacteria, Coastal Soil

In the present investigation, several residues from agro-forestry industries such as rice straw acid hydrolysate, corn cob acid hydrolysate, tomato juice, cane molasses and orange pulp were evaluated as the economical source for the production of bacterial cellulose. The bacterial cellulose attained the significant yield of 7.8 g/L using tomato juice, followed by 3.6 g/L using cane molasses and 2.8 g/L using orange pulp after 7 days of incubation. Furthermore, the optimum pH and temperature of fermentation for maximum production of bacterial cellulose was 4.5 and 30 ± 1 °C. The identified bacterium Acetobacter pasteurianus RSV-4 has been deposited at repository under the accession number MTCC 25117. The produced bacterial cellulose was characterized through FTIR, SEM, TGA and DSC and found to be of very good quality. The bacterial cellulose produced by identified strain on these various agro-waste residues could be a cost effective technology for commercial its production.

In the recent years, worldwide and environmental issues have prompted the developers to re-direct their to bio-based resources even in the medical sector. In this context, bacterial cellulose based materials are the upcoming area of research due to its potential medical application in the wound healing field. On the contrary, there are several natural antiseptic materials available out of which the Beeswax, a well- known material which suits requirements for the development of a medical textile material for the purpose of wound healing. Beeswax is a natural animal wax which has various properties in addition to its biocompatible nature. Beeswax, an excellent emulsion stabilizer and water-repellent enhancer is coated over the textile fabrics to remove the surface roughness, The chemical constituents of beeswax varies according to the geographic region. Beeswax enhances water repellency and emulsifies insoluble particles in textile fabrics. Vitamin A, which is an essential for human cell development is a major composition in the Beeswax. Nata de Coco, a typical bacterial cellulose is the most popular one in the production of nata. Nata is the fermentation product of the bacteria, Acetobacter xylinium referred to as Nata de Coco, Nata de Pina whereby their flavors are controlled by the coconut water based and pineapple based cultures respectively. Nata de Coco marks a remarkable application in the wound healing process for the second degree burns. In this present study, the superficial water-repellency for the beeswax coated fabrics and the artificial developed bacterial cellulose material called Nata de Coco is being compared which will further take the development process to the next stage This forms a major base for the development of various biomaterials.

In this research batch reactors were operated with coffee processing waste and autochthonous microbial consortium, and a taxonomic and functional analysis was performed for phase I of stabilization of maximum H2 production and for phase II of maximum H2 consumption. During phase I, the reactor's operating conditions were pH 4.84 to 8.18, headspace 33.18% to 66.82%, and pulp and husk from 6.95 to 17.05 g/L. These assays continued for phase II, with initial pH conditions of 5.8-8.1, headspace of 33.18-66.82%, and pulp and husk remaining from phase I. The highest homoacetogenesis was observed in assay 5 with pH 7.7, 40% headspace, and 15 g/L of pulp and husk (initial concentrations of phase I). A relative abundance of Clostridium 41%, Lactobacillus 20% and Acetobacter 14% was observed in phase I. In phase II, there was a change in relative abundance of 21%, 63%, and 1%, respectively, and functional genes involved with autotrophic (formyltetrahydrofolate synthase) and heterotrophic (enolase) homoacetogenesis, butanol (3-hydroxybutyryl-CoA dehydrogenase), and propionic acid (propionate CoA-transferase) were identified. This study provides a new and amplified insight into the physicochemical and microbiological factors, which can be used to propose adequate operational conditions to maximize the bioenergy production and reduce homoacetogenesis in biological reactors.

4 Tablas.-- 4 Figuras, A new aeration treatment of black ripe olive streams prior to their vacuum evaporation was studied. It was found that the aeration for two days of these solutions reduced the chemical oxygen demand (COD) of the distillate phase (>80%) generated during their vacuum evaporation; although the temperature (14–38 °C) and the air flow rate (10–50 L air/h/L) had a great influence on this reduction. Moreover, the COD in the distillate was mainly associated with the presence of acetic acid (~400 mg/L) and ethanol (~500 mg/L), the later substance being eliminated by strong aeration. Additionally, the growth of native aerobic microorganisms, mainly Acetobacter, increased the pH of the wastewater to 7–8 units, thus avoiding evaporation of the acetic acid salt formed. These results make the use of the distillate for plant irrigation viable and its discharge into municipal depuration plants possible, given the low COD (, This work was supported by the Spanish Government (Project AGL2016-76820-R, AEI/FEDER, UE).

Microbial contamination of fuels, associated with a wide variety of bacteria and fungi, leads to decreased product quality and can compromise equipment performance by biofouling and microbiologically influenced corrosion of pipelines and storage tanks. Detection and quantification of biomass are critical in monitoring fuel systems for an early detection of microbial outbreaks. The aims of this study are (i) to quantify bacterial and fungal contamination in samples from diesel storage tanks of petrol stations, using both culture dependent- and culture independent (qPCR) approaches, and (ii) to analyse the diversity of cultivable diesel-contaminating microorganisms with the purpose to create a strain collection for further use in biodeterioration experiments. Both methodological approaches revealed a high microbial contamination in all studied samples, with the bacterial load being much higher than the fungal load. The diversity of cultivable microorganisms was rather low. Based on criteria of abundance and fuel degradation potential, the most relevant microorganisms were identified as bacteria of genera Bacillus , Citrobacter , Burkholderia and Acetobacter , the filamentous fungi Paecilomyces variotii and Pseudallescheria boydii , and a Dipodascaceae yeast. Furthermore the validity and utility of qPCR-based methods are discussed.

Bacterial cellulose (BC) is a naturally produced as an exopolysaccharide from some bacteria. It has excellent properties over the plant cellulose and has numerous applications in many fields including food, pharmaceutical, textile, paper manufacturing and other industries. However, a major limitation of bacterial cellulose production is the high cost of carbon substrate. The study aims to reduce the cost of bacterial cellulose using a cheap carbon source. This study presents feasibility in the production of bacterial cellulose using the starchy effluent waste from the Thai fermented rice noodle manufacturing process as a low-cost substrate by Acetobacter xylinum TISTR 975. The optimizations of culture conditions for bacterial cellulose production were also investigated under static culture. The results indicated that starchy effluent waste from the Thai fermented rice noodle manufacturing process performs well for the production of bacterial cellulose by supplementing with 50 g/L sucrose and 2% olive oil under the static condition. The structure and physical properties of bacterial cellulose were characterized using SEM, FTIR and XRD. In summary, the starchy effluent waste from the Thai fermented rice noodle manufacturing process can be used to produce bacterial cellulose which is a high value-added, sustainable and green product.

Shake-flask cultures of microorganisms involve flame sterilization during sampling, which produces combustion gas with high CO2 concentrations. The gaseous destination has not been deeply analyzed. Our aim was to investigate the effect of flame sterilization on the headspace of the flask and on the shake-flask culture. In this study, the headspace CO2 concentration was found to increase during flame sterilization ~0.5–2.0% over 5–20 s empirically using the Circulation Direct Monitoring and Sampling System. This CO2 accumulation was confirmed theoretically using Computational Fluid Dynamics; it was 9% topically. To evaluate the influence of CO2 accumulation without interference from other sampling factors, the flask gas phase formed by flame sterilization was reproduced by aseptically supplying 99.8% CO2 into the headspace, without sampling. We developed a unit that can be sampled in situ without interruption of shaking, movement to a clean bench, opening of the culture-plug, and flame sterilization. We observed that the growth behaviour of Escherichia coli, Pelomonas saccharophila, Acetobacter pasteurianus, and Saccharomyces cerevisiae was different depending on the CO2 aeration conditions. These results are expected to contribute to improving microbial cell culture systems.

Physiological responses to changes in environmental conditions such as temperature may partly arise from the resident microbial community that integrates a wide range of bio-physiological aspects of the host. In the present study, we assessed the effect of developmental temperature on the thermal tolerance and microbial community of Drosophila melanogaster. We also developed a bacterial transplantation protocol in order to examine the possibility of reshaping the host bacterial composition and assessed its influence on the thermotolerance phenotype. We found that the temperature during development affected thermal tolerance and the microbial composition of male D. melanogaster. Flies that developed at low temperature (13°C) were the most cold resistant and showed the highest abundance of Wolbachia, while flies that developed at high temperature (31°C) were the most heat tolerant and had the highest abundance of Acetobacter. In addition, feeding newly eclosed flies with bacterial suspensions from intestines of flies developed at low temperatures changed the heat tolerance of recipient flies. However, we were not able to link this directly to a change in the host bacterial composition.

Background/Objectives: In India the increase in population and industrialisation, there is a much need for the soil to be used for various activities. There is a need to improve the properties of soil, if the soil at any particular locality is unsuited, wholly or partially selected for the construction. With increasing awareness of environmental issues, there has been a remarkable shift toward “green” and sustainable technologies. In view of these attempt is made to study the new sustainable method of biogeochemical techniques to improve the soil properties. Methods: In this work test for the Unconfined Compressive Strength (UCS) for soils were conducted as per IS to know variation in strength characteristics with the addition of two bacteria namely Acetobacter and Bacillus of different incubation periods and curing periods. For the same soil samples, the free swell index values were also determined to know the effect of addition of bacteria by stabilisation. Findings: The UCC test results for the soil samples treated with bacteria showed an increase in strength of soil with the increase in age of bacteria. The increase in Unconfined Compressive Strength (UCS) value at 60 day curing period is about 175% for soil treated with Acetobacter and 520% for Bacillus. Swelling characteristics also reduced by the treatment with Acetobacter and Bacillus bacteria. Improvement/Applications: Biostabilisation with bacteria proved the increase in strength and decrease in swell it can be used as an innovative stabiliser for stabilising problematic soils, which is cost-effective, non intrusive, low energy demanding and ecofriendly.

BACKGROUND: The acetification process needs an overall study of the variables influencing it in order to establish their optimum values. Based on industrial experience and available literature, including a recently proposed model by the authors, among the variables most strongly influencing the acetification process are the ethanol concentration at the time the reactor is unloaded, the unloaded volume and the loading rate. To ensure economically efficient industrial production of vinegar, and to check the predictions of the aforementioned model, the influence of the final ethanol concentration at unloading time on the mean acetification rate and on productivity has been studied in this work. RESULTS: An increase in the final ethanol concentration from 0.5 to 3.5% (v/v) increased the mean overall acetification rate and acetic acid production by 38 and 26%, respectively. The increase was established mainly during the loading phase. CONCLUSIONS: The final ethanol concentration is a key variable for process optimization. If a high rate is desired then a product containing much unused substrate will be obtained, which may be industrially unacceptable. These results suggest the necessity to investigate other possibilities when high values for yield and productivity must to be achieved. Copyright © 2010 Society of Chemical Industry

Microbial cellulose is a pure form of cellulose with widespread applications. It is very applicable for medical usage specially wound dressings due to its high liquid absorbency and hygienic nature. In this study, microbial cellulose formed/coated on cotton gauze samples during its biosynthesis in a static medium (Hestrin & Scharm) for 6 days by Acetobacter Xylinium. Some essential factors of treated gauze samples, like water absorbency, drying time (water holding time), and amount of vertical wicking were determined and compared with untreated samples. Results showed that cotton gauze coating with microbial cellulose increases water absorbency and wicking ability over 30%, and reduces drying time about 33%. It can be concluded that covering of cotton gauze with microbial cellulose can promote some important characteristics of it specially for wound dressings.

The performance of biological phosphorus removal (BPR) in a sequencing batch reactor (SBR) with single-stage oxic process was investigated using simulated municipal wastewater. The experimental results showed that BPR could be achieved in a SBR without anaerobic phase, which was conventionally considered as a key phase for BPR. Phosphorus (P) concentration 0.22–1.79 mg L −1 in effluent can be obtained after 4 h aeration when P concentration in influent was about 15–20 mg L −1 , the dissolved oxygen (DO) was controlled at 3 ± 0.2 mg L −1 during aerobic phase and pH was maintained 7 ± 0.1, which indicated the efficiencies of P removal were achieved 90% above. Experimental results also showed that P was mainly stored in the form of intracellular storage of polyphosphate (poly-P), and about 207.235 mg phosphates have been removed by the discharge of rich-phosphorus sludge for each SBR cycle. However, the energy storage poly-β-hydroxyalkanoates (PHA) was almost kept constant at a low level (5–6 mg L −1 ) during the process. Those results showed that phosphate could be transformed to poly-P with single-stage oxic process without PHA accumulation, and BPR could be realized in net phosphate removal.

Some Acetobacter strains produce a cellulose called bacterial cellulose in culture medium. This cellulose has unique structural and mechanical properties compared with higher plant cellulose, and is expected to be a commodity material in various fields of industry. For economical mass production, it is essential to construct an aeration and agitation culture process. To explore the industrial applications of the bacterial cellulose, the structural features and physicochemical properties need to be understood and potentially improved. This paper reviews recent progress in research on this bacterial cellulose.

An anaerobic digestion technique was applied to azo-reactive dye aqueous solutions and cotton textile wastewater aiming at the color elimination. A batch-mode water-jacketed anaerobic reactor and acclimatized acetate-consuming bacteria initially derived from the anaerobic digester sludge of a municipal wastewater treatment plant were used for this study. Acetic acid solution and a pH-controller were utilized to maintain the pH at the desired level (6.6–7.2) while the temperature was kept constant at 37 °C using an external water-bath. Acetic acid also served as an external substrate (electron-donor) supply for the bacteria metabolism. Complete decolorization of all dye solutions was succeeded in 4–5 days of experimental run. The biodegradation ability of cotton textile wastewater was also examined without the addition of external substrate supply (acetic acid) resulting to poor decolorization results. However, anaerobic digestion of the same wastewater using the acetate-consuming bacteria and acetic acid as an external substrate supply lead to the complete decolorization of the wastewater in 4 days of experiment.

Methods of adapting micro-organisms to an inhibiting factor in an active industrial bioprocess were examined with an acetic acid fermentation as model. With the aim of automatic control, a fuzzy-logic system was developed on the basis of the collected knowledge of skilled vinegar brewers. In a first step, this fuzzy system was to assess the actual adaptation degree of the bacteria on the basis of data from robust and reasonably priced sensors. From this information an appropriate setpoint value for the inhibiting factor ‘final acid concentration’ was derived for each batch cycle. As a result a further acid tolerance was found after several batch cycles. This adaptation effect should be used to increase the product concentration to more than 20 g per 100 ml acetic acid with a high productivity. The stepwise adapted culture was productive over the aimed acetic acid concentration, a 10% improvement of the product formation rate could be found compared with the status before conditioning. High product concentration and increased productivity finally result in shorter cycle times, less transport and storage volumes, an improved utilization of energy and material resources, and, last but not least, they are an essential steps towards the fulfillment of economical and ecological demands.

Aims To maximize acetification rate (ETA) by adsorption of acetic acid bacteria (AAB) on loofa sponge matrices (LSM). Methods and Results AAB were adsorbed on LSM, and the optimal shaking rate was determined for maximized AAB growth and oxygen availability. Results confirm that the 1 Hz reciprocating shaking rate with 40% working volume (liquid volume 24 l, tank volume 60 l) achieved a high oxygen transfer coefficient (kLa). The highest ETA was obtained at 50% (w:v) LSM-AAB:culture medium at 30 ± 2°C (P ≤ 0·05). To test process consistency, nine sequential acetification cycles were run using LSM-AAB and comparing it with no LSM. The highest ETA (1·701–2·401 g l−1 d−1) was with LSM-AAB and was associated with the highest biomass of AAB, confirmed by SEM images. Conclusions Results confirm that LSM-AAB works well as an inert substrate for AAB. High oxygenation was maintained by a reciprocating shaker. Both shaking and LSM were important in increasing ETA. Significance and Impact of the Study High cell biomass in LSM-AAB provides good conditions for higher ETAs of quick acetification under adequate oxygen transfer by reciprocating shaker. It is a sustainable process for small-scale vinegar production system requiring minimal set-up cost.

With the aim of improving bacterial cellulose (BC) production in an aerated and agitated culture, the effects of the oxygen and carbon dioxide pressures were investigated. The BC production rate was dependent on the oxygen transfer rate, which declined as the broth viscosity increased, accompanied by BC accumulation. Increasing the partial pressure of oxygen by sparging with oxygen-enriched air and/or raising the operating pressure improved the oxygen supply, while the agitation power required was lowered. Although the BC production rate was not affected by higher oxygen pressure, it was reduced as the operating pressure was raised. The reduction in the production rate was considered to be due to the high carbon dioxide pressure, because carbon dioxide-enriched air also reduced the BC production rate, while the reduction was canceled out by increasing the air flow rate.

The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a "core" and a "variable" part. The bacterial populations show a remarkable consistency, with only two dominant species, Lactobacillus fermentum and Acetobacter pasteurianus. The fungal diversity is much larger, with four dominant species occurring in all fermentations ("core" yeasts), and a large number of yeasts that only occur in lower numbers and specific fermentations ("variable" yeasts). Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of Saccharomyces cerevisiae. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency. ispartof: PLOS ONE vol:8 issue:12 ispartof: location:United States status: published

The coproduction of a useful material and electricity via a novel application of microbial fuel cell (MFC) technology to oxidative fermentation was investigated. We focused on vinegar production, i.e., acetic acid fermentation, as an initial and model useful material that can be produced by oxidative fermentation in combination with MFC technology. The coproduction of acetic acid and electricity by applying MFC technology was successfully demonstrated by the simultaneous progress of acetic acid fermentation and electricity generation through a series of repeated batch fermentations. Although the production rate of acetic acid was very small, it increased with the number of repeated batch fermentations that were conducted. We obtained nearly identical (73.1%) or larger (89.9%) acetic acid yields than that typically achieved by aerated fermentation (75.8%). The open-cycle voltages measured before and after fermentation increased with the total fermentation time and reached a maximum value of 0.521 V prior to the third batch fermentation. The maximum current and power densities measured in this study (19.1 μA/cm2 and 2.47 μW/cm2, respectively) were obtained after the second batch fermentation.

Organic synthetic polymers such as polyacrylamide derivates, polythylenimine, Na polyacrylates etc. have received much attention as flocculating substances used in waste water treatment. There is an urgent need for the production of effective flocculants to replace mechanical separation methods or, at least, to optimize them. Biological safety and decomposition are essential pre-requisits for utilizing flocculants produced by microbial processes (e.g. discontinuous and continuous cultivation of bacteria or yeasts). The extracted polymers consisting of proteins, lipids, nucleic acids and polysaccharides are capable of being degraded easily by microbiological reactions because they are natural compounds. The induction phase of excreting cellularic biopolymers is the crucial stage. In the special literature, low pO2 levels associated with a high concentration of the carbon source, limitation of N, P and trace elements have been recommended for the induction of excreting exopolymers. In order to ensure sufficiant induction, we preferred a special procedure, the main characteristic of it being changed between limitation and excessive supply of components essential for the growth of microorganisms. The quality control of exopolysaccharides for flocculation was determined by turbidimetric methods and sedimentation tests with caoline as a standard substance. For the initial investigations Acetobacter methanolicus and methylobacterium rhodesianum were used.

The modeling and optimization of industrial processes requires an intensive study of the factors involved. In this work, a continuous pilot system for studying the industrial process of acetic fermentation is developed. A Doehlert design is applied to the five variables involved in the pilot process. This experimental design allows reduction of the experimental burden and the maximum amount of information to be obtained, studying the factors at different levels depending on their significance. The experimental system provides a robust measure of the specific growth rate and the rates of substrates consumption and acetic acid production, related to the flow of effluent stream evaluated in the steady state. The results demonstrate the growth-associated kinetics of substrates and product, and the yield factors are calculated with low values of variances for the coefficients, i.e., within the range 1-11%. The specific growth rate suits the quadratic model proposed. The response surfaces generated by the model are applied to explain the behavior of the bacterial growth and, therefore, the effects of the process variables studied over the acetic acid production. Very low levels of ethanol or oxygen make the acetification rate decrease, and a saturation effect with high levels of ethanol or oxygen is also deduced. The effects of the aeration rate, agitation, and overpressure suggest a kind of inhibition of the acetic acid production caused by the oxygen that has not been practically studied before. The temperature strengthens the inhibitory effect of the ethanol and the oxygen. The conclusions of this work consolidate the structure of a hybrid model for the acetic fermentation.