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Microbial fuel cells (MFCs) are often discussed as a part of a sustainable generation of electricity for the coming 'energy revolution'. In particular, the application of MFCs in wastewater treatment plants (WWTPs) are often regarded as an attractive alternative to reduce costs while generating electricity. Field surveys are necessary to show the applicability of MFCs in WWTPs considering daily fluctuations and environmental effects such as rain events affecting the MFC performance remarkably. In this study, a MFC system was tested in four municipal WWTPs using different modes of operation. A correlation between current densities and sludge loading (SL) was identified. At low SLs, the activated sludge needs a large amount of the energy derived from the substrate for the maintenance metabolism resulting in quite low current densities of the MFC. At high SLs much more of the energy can be transferred from the activated sludge to the electrode, resulting in higher currents. Furthermore, the effect of environmental conditions on the current densities was evaluated. WWTPs have daily fluctuations depending on the wastewater composition, weather phenomena and population equivalents. Our data show that these daily fluctuations can only be observed in the MFC performance at WWTPs below 50,000 population equivalents.

Microbial fuel cells (MFCs) are devices generating electrical current from a wide range of organic substrates by using bacterial metabolism. Integrations of MFCs into wastewater treatment plants seem to be the most likely application of this technology. Due to the fact that the current flow in a MFC is fundamentally produced by the metabolic activity of microorganisms, it would be desirable to elucidate the capacity of the microbial systems to optimize the energy extraction processes in MFCs. In this study, the correlation between the parameters XBH (active heterotrophic biomass) and XBA (active autotrophic biomass) from the established activated sludge model number 1 (ASM1) and the measured current flow in MFCs was investigated for the first time. The simulation protocol based on ASM1 shows a good congruence between measured and simulated effluent values for the wastewater treatment plant. Comparisons between the measured current densities and the simulated concentrations of active biomass showed linear correlations at substrate pulses and at different residence times of the substrate. Therefore, it can be concluded that the model parameter XBH and XBA of the ASM1 can be used to estimate the current output of a MFC in wastewater treatment plants. The identified correlations can be used to optimize operating conditions and to generate high current outputs of the MFCs based on simulations.

The proliferation of pharmaceuticals and chemicals and the increasing manufacture of medical goods have made an assessment of their potential toxicological risks to man and the environment indispensable. Hence, a wide range of tests has been developed in order to generate data on the harmful effects of chemicals and pharmaceuticals on organisms. Initially, toxicological data were commonly collected from tests involving animals; however, on account of ethical objections, they are gradually being replaced by in vitro cytotoxicity tests. In this work, a new in vitro screening method for the determination of cytotoxicity, based on a novel electrochemical bioactivity sensor system, was implemented. The evaluation was based on current–time curves of a potentiostatic measurement proportional to the reduction of mediator molecules by mammalian cells. Depending on the number of reduced mediator molecules used by the cells, a current signal is produced, which provides information about the viability of living cells. By adding a toxic test substance to the cell, a reduction in the current signal can be observed, depending on the cytotoxicity of the substance. It is possible to quickly create a specific cytotoxic curve and to determine the corresponding inhibitory concentrations (IC50 value). First tests were performed on three mammalian cell lines and eight model compounds using this electrochemical measurement system. The IC50 values obtained corresponded well with the toxicity determined with an established reference cytotoxicity assay (MTT test) and with data reported in the literature.

Methanol is one of the building blocks in the chemical industry and can be synthesized either from petrochemical or renewable resources, such as biogas. Bioprocess technology with methylotrophic bacteria is well established, as illustrated by large-scale single-cell protein production in the past. During recent years, the first genomes of methylotrophs have been sequenced and significant progress in elucidating their metabolism has been made. In addition, the tool set for genetic engineering of methylotrophic bacteria has expanded greatly and strategies to produce fine and bulk chemicals with methylotrophs have been described. This review highlights the potential of these bacteria for the development of economically competitive bioprocesses based on methanol as an alternative carbon source, bringing together biological, technical and economic considerations.

Angesichts hoher Olpreise und der sich abzeichnenden globalen Klimaveranderungen erscheinen biotechnisch hergestellte Energietrager als vielversprechende Zukunftsoption. Mit seinen Jahresproduktionsmengen von 2 Mio t Biodiesel, 560.000 t Bioethanol und seinen 2.700 Biogasanlagen befindet sich Deutschland in Sachen Bioenergie in der vorderen Halfte der Industrienationen. Vorgestellt werden die Moglichkeiten, die die weise Biotechnologie zur Herstellung von Energietragern bietet. In view of the high price of oil and the emerging global climate changes, biotechnologically produced energy sources appear to be a promising option for the future. Of the industrial nations, Germany with annual production figures of 2 m tons of biodiesel, 560,000 tons of bioethanol and some 2,700 biogas plants is in the upper half of the bioenergy rankings. Here, the potential of industrial biotechnology for energy production is presented in detail.

Methoden der technischen Chemie spielen bei der Prozessintensivierung und der weisen Biotechnologie eine wichtige Rolle. Der gestiegene Erdolpreis und die Sorge um das Klima rucken nachwachsende Rohstoffe in das Blickfeld. Die Katalyse wird bei der mittelfristig bevorstehenden Veranderung der Rohstoffbasis einen grosen Einfluss haben.

Potential-controlled chromatography is introduced as a new technique for the separation of amino acids and peptides. The principle of potential-controlled chromatography depends on the use of electrically conductive material as the stationary phase of the chromatographic column. Thus from an electrochemical point of view the packed column can be regarded as a packed-bed electrode. The electrical potential of this stationary phase can be controlled by a potentiostat. The separation of amino acid and peptide molecules during their migration through the column depends on their own electric charge on the one hand and on the electrical potential of the stationary phase on the other. The chromatographic separation of some amino acids could be demonstrated.

Die Weise Biotechnologie ist keine neue Disziplin, sondern fasst nur ein Segment der Biotechnologie zusammen, um sie von den beiden anderen grosen Segmenten – der Roten und der Grunen Biotechnologie – abzuheben. Sie ist in den Fokus geraten, weil bahnbrechende Verfahren zur Analyse biologischer Systeme eine Neubetrachtung der Potenziale der Biotechnologie zur Folge haben. Neue Entwicklungen sind abzusehen, wie uber genombasierte Daten mit Hilfe der Bioinformatik, der Molekularbiologie und der Bioverfahrenstechnik Prozesse in ganzheitlicher Betrachtung optimiert werden. Wegen relativ einfacher biologischer Systeme, aber vielfaltiger Anwendungen wird die Weise Biotechnologie als Vorreiterdisziplin ins Feld gefuhrt. Durch die Forderung interdisziplinarer Ansatze zur integralen Prozessentwicklung sollte die biotechnologisch orientierte Industrie in weitem Mase profitieren. Dies gilt insbesondere fur das wissenschaftliche Umfeld und die kleinen und mittleren Unternehmen, die mehr und mehr vom Zugang zu den modernen Methoden der Biotechnologie abhangen. Im internationalen Rahmen ist gerade auf dem Gebiet der Weisen Biotechnologie eine konkurrenzfahige Situation in Deutschland festzustellen. Es bedarf jedoch einer nachhaltigen und langfristigen Unterstutzung, damit sowohl die Wissenschaft als auch die Industrie nicht den Anschluss an die internationale Entwicklung der Weisen Biotechnologie verlieren.

Selective transformations of limonene by asco- and basidiomycetes were investigated. On the shake flask scale, Penicillium citrinum hydrated R-(+)-limonene to α-terpineol [83% regioselectivity (rs), more than 80 mg 1-1 product yield], and Gongronella butleri catalysed the terminal oxidation to yield perillyl alcohol (60% rs, 16 mg 1-1). On the laboratory bioreactor scale, Penicillium digitatum produced a peak concentration of 506 mg α-terpineol 1-1 in the fed-batch mode, equivalent to a theoretical yield of 67%, and no volatile by-products were found. Fusarium proliferatum transformed R-(+)-limonene enantiospecifically to cis-(+)- carveol (98.6% ee, more than 35 mg 1-1 product yield) and S-(-)-limonene predominantly to trans-(-)-carveol (96.3% ee). Pleurotus sapidus selectively dehydrogenised the accumulating trans-(-)-carveol to the corresponding enantiopure R-(-)-carvone. The results show that a careful selection of strain and bioprocess parameters may improve both the yield and the optical purity of a desired product.

An integrated bioprocess for the production of the natural rose-like aroma compounds, 2-phenylethanol (2-PE) and 2-phenylethylacetate (2-PEAc), from L-phenylalanine (L-phe) with yeasts was investigated. The hydrophobicity of the products leads to product inhibition, which can be compensated by in situ product removal (ISPR). An organophilic pervaporation unit, equipped with a polyoctylmethylsiloxane (POMS) membrane, was coupled via a bypass to a bioreactor and proved to be a suitable technique for the in situ removal of high-boiling products from culture broth. With batch cultures of the thermotolerant yeast Kluyveromyces marxianus CBS 600 in a standard medium at 35 degrees C, the use of pervaporation resulted in a double 2-PE concentration (2.2 g/L) and 1.3 g/L 2-PEAc, which only accumulated transiently in low concentrations during cultivation without ISPR. Using a previously optimized medium, the variation of the temperature from 30 degrees C to 40 degrees C caused an increase in the total conversion yield from 63% to 79%, corresponding to total product concentrations of 5.23 and 5.85 g/L, respectively. In the 40 degrees C batch experiment, the volumetric productivity (2-PE + 2-PEAc) during the exponential phase was 5.2 mmol/L h. While for 2-PE, there is still potential for further optimization, the more hydrophobic 2-PEAc was nearly completely removed from the aqueous culture broth (enrichment factor >400), resulting in highly aroma-enriched permeates. Due to the temperature-correlated performance of the pervaporation, the bioconversion was still efficient even at 45 degrees C (conversion yield: 69%). Surprisingly, at 45 degrees C, the molar ratio of the two products inverted and 2-PEAc turned out to be the main product (4.0 g/L), which opens easy control of the reaction's selectivity by external means. Retrofitting the process with interim heating and cooling equipment to use different temperature levels for cultivation and pervaporation resulted in a decreased yield and product concentration caused by multiple stress factors. The medium composition affected the pervaporation efficiency with molasses acting detrimental.

The application of a simple system for measuring the oxygen uptake rate (OUR) to determine the activity of pellet-forming fungi is described. A non-invasive easy-to-use respirometric system was used to measure the OUR as an activity parameter. The model sensor system was optimized in shake flask experiments with Pleurotus sapidus (DSMZ 8266) and Chaetomium globosum (DSMZ 1962). The toxicity of (+)-limonene and (+)-valencene to submerged fungal cultures and the influence of solvents on C. globosum were investigated. Finally, the new respirometric method was used for the determination of oxygen uptake rates in small scale bioreactors to control the activity of terpene transforming fungi.

Using a genetic algorithm, 13 medium constituents and the temperature were varied to improve the bioconversion of l -phenylalanine ( l -phe) to 2-phenylethanol (2-PE) with Kluyveromyces marxianus CBS 600. Within four generations plus an additional temperature screening, corresponding to 98 parallel experiments altogether, a maximum 2-PE concentration of 5.6 g/l, equivalent to an increase of 87% compared to the non-optimized medium was obtained. The vitamin content of the medium had to be raised significantly.

Fourteen yeast strains were screened for production of 2-phenylethanol from l-phenylalanine with molasses as carbon source. Up to 1 g 2-phenylethanol l−1 was obtained. Using oleyl alcohol as a second phase for in situ product removal to enhance the production of 2-phenylethanol increased the yield to about 3 g 2-phenylethanol l−1 at 35 °C. The most productive strains were Kluyveromyces marxianus CBS 600 and CBS 397.

The application of starter cultures in the food industry is a widely used method of deliberately initiating fermentations of foodstuffs. Batch-dependent fluctuations in the activity of starter cultures can have an adverse effect on the quality of the products to be made using them. The amperometric sensor system presented in this study is able to detect deficiencies in the quality of starter cultures, thus enabling the end-user to adapt production steps according to the culture applied. The principle of the sensor system is current measurement by way of a three-electrode system. The current signal is based on a mediator, which has been reduced by microorganisms, immobilised in a gel together with the microorganisms.

The microbial activity of aerobic heterotrophic, anoxic heterotrophic and aerobic autotrophic microorganisms in biological wastewater treatment was determined by means of an electrochemical bioactivity sensor. The development of the sensor resulted in a system which can determine the microbial activities that are relevant for effective wastewater treatment. The signals of the sensor system are proportional to the substrate degradation and it can show inhibiting effects on the biomass. The most important advantages of the system are: it is independent of O2 consumption, the three most important types of metabolic activities in wastewater technology can be measured with one sensor, furthermore the measurement is suitable for automation and it is on-line. The result is a potential for the optimization of processes based on microbial activity.

INTRODUCTION TO RENEWABLE RESOURCES IN THE CHEMICAL INDUSTRY PLANTS AS BIOREACTORS: PRODUCTION AND USE OF PLANT-DERIVED SECONDARY METABOLITES, ENZYMES, AND PHARMACEUTICAL PROTEINS Introduction Renewable Resources in the Chemical Industry Fine Chemicals and Drugs Plant-Made Pharmaceuticals WORLD AGRICULTURAL CAPACITY Petrochemicals Today Renewable Chemicals Agricultural Production Supplying the Chemical Industry Summary LOGISTICS OF RENEWABLE RAW MATERIALS Introduction Determining Factors for the Logistics of Industrial Utilization Chains for Renewable Raw Materials Processing Steps of Renewable Raw Material Logistic Chains Design and Planning of Renewable Raw Material Logistic Chains Summary and Conclusions EXISTING VALUE CHAINS Industrial Biotechnology Today - Main Products, Substrates, and Raw Materials White Biotechnology - Future Products from Today's Raw Materials? Effects of Feedstock and Process Technology onthe Production Cost of Chemicals New Raw Materials for White Biotechnology Case Studies: Lignocellulose as Raw Material and Intermediates Case Studies: "SCOs" as Raw Material and Intermediate Conclusions FUTURE BIOREFINERIES Introduction Current and Future Outlook for Biofuels Chemicals from Renewable Resources The Role of Clean Technologies in Biorefineries The Size of Future Biorefineries Conclusions ECONOMIC AND SOCIAL IMPLICATIONS OF THE INDUSTRIAL USE OF RENEWABLE RAW MATERIALS Introduction Biorefinery Industry and the Development of EU Rural Areas From Analytic to Systemic Modeling Methodology of the Biorefinery Industry Stakeholders' Perceptions of Biorefinery in Rural Areas: Issues and Lessons from the South of Italy Concluding Remarks BIOBASED PRODUCTS - MARKET NEEDS AND OPPORTUNITIES Introduction Definition Basic Technology for the Conversion of Renewable Raw Materials Classes of Bioproducts Current Status Outlook and Perspectives LIFE-CYCLE ANALYSIS OF BIOBASED PRODUCTS Introduction: Why Life-Cycle Analysis of Biobased Products? The Methodological Framework of LCA Specific Methodological Aspects for LCA for Biobased Products LCA Studies for Biobased Products: Major Findings and Insights Conclusions CONCLUSION

The article contains sections titled: 1. Introduction 2. Basics in Microbiology 2.1. Microbiology – the Science of Microscopic Life Forms 2.2. Phylogeny and Taxonomy of Microorganisms 2.2.1. Definition and Survey 2.2.2. Bacteria 2.2.3. Archaea 2.2.4. Morphological and Physiological Properties for the Identification of Prokaryotic Species 2.2.5. Eukaryotic Microorganisms 2.2.5.1. Definition 2.2.5.2. Fungi 3. Metabolism 3.1. Microbial Systems Biology 3.2. Energy Production 3.3. Substrate Transport 3.4. Catabolism 3.4.1. Photosynthesis 3.4.2. Chemosynthesis 3.4.3. Carbohydrate Metabolism 3.4.4. Aerobic Processes 3.4.5. Fats and Fatty Acid Metabolism 3.4.6. Hydrocarbon Metabolism 3.4.7. Amino Acid Metabolism 3.4.8. Anaerobic Metabolic Processes 3.4.9. Single-Carbon-Compound Metabolism 3.4.10. Inorganic Metabolism 3.5. Biosynthesis 3.5.1. Amino Acids 3.5.2. Lipids 3.5.3. RNA and DNA 3.6. Regulation Biotechnology can be regarded as one of the key technologies of the 21st century. It is the commercial application of living organisms such as bacteria, fungi, yeasts, plant cells, viruses, and mammalian cells or their products, which involves the deliberate manipulation of their DNA molecules. This article gives an introduction into the basics in microbiology and provides an exhaustive description of the relevant microbial species and metabolic pathways. Identification, analysis, and manipulation of the genome, proteome, and metabolome is described, and cultivation requirements as well as process parameters discussed. Biotransformation and enzyme technology plays a central role in industrial biotechnology, and a focus is given on the development of molecular engineering techniques and new screening methods. Computational Biochemistry comprises the definition, monitoring, and modeling of bioprocesses. Examples of biotechnology applications include mammalian cell technology, tissue engineering, and the production of relevant food additives as well as of various medical and pharmaceutical products. In conclusion, biotechnology offers manifold possibilities in industrial and medical applications.

In a biochemical fuel cell different microorganisms were employed as biocatalysts and 2-hydroxy-1,4-naphthoquinone as a redox mediator. An oxygen gas diffusion electrode was used successfully; by means of a packed bed electrode as an anode the electricity output of the fuel cell could be raised considerably. Even a mixed population from a plant for the biological treatment of industrial waste gas was successfully utilized as a biocatalyst.—Experiments were carried out using the biofuel cell for bioanalytical and biosensor purposes.—Microbial mediator reduction, which is the key reaction of such a fuel cell, was examined separately for different microorganisms.

Biotechnological processes or process steps can substitute traditionally applied techniques. Of all the arguments to be considered when choosing a biotechnical process, improving the process economy is the most important one.

Nachwachsende Rohstoffe werden in der Zukunft auch in der chemischen Industrie immer grosere Bedeutung erlangen. Im Kontext der Weisen Biotechnologie stellen sie den Schnittpunkt zwischen der Landwirtschaft und der chemischen Industrie dar. Durch die Verknappung und durch die damit verbundene Verteuerung der fossilen Rohstoffe stellen die nachwachsenden Rohstoffe eine interessante Alternative dar. Betrachtet man die Produktion von Bulk-Chemikalien, so wird deutlich, dass fur diesen Bereich neben den C-Quellen Zucker und Starke neue Rohstoffquellen erschlossen werden mussen. Hier bietet sich die Nutzung von Lignocellulose an. Verbunden mit der stofflichen sollte es aber auch eine energetische Nutzung geben. In diesem Beitrag werden diese interessanten Zukunftsfelder diskutiert – insbesondere auch aus der Sicht der Industrie.

Nineteen different fungi were screened to test their capability to convert (±)-linalool into lilac aldehydes and lilac alcohols. Solid phase microextraction (SPME) in combination with GC-MS was used to identify the target compounds by comparing retention times and mass spectra with chemically synthesised standards. Most of the strains showed specific and complex product spectra, often with linalool oxides and dihydrolinalool as major metabolites. Aspergillus niger DSM 821, Botrytis cinerea 5901/02 and Botrytis cinerea 02/FB II/2.1 generated the desired lilac fragrance compounds as metabolic by-products.

Integrated bioprocess concepts specific to the requirements of monoterpenes as precursors of microbial transformations were developed. R -Limonene and α-pinene were used as model precursors and bacteria and higher fungi served as biocatalysts. A closed-gas-loop bioreactor was set up to address the volatility of terpenoids. By this means α-terpineol was produced from R -limonene at the gram per litre scale with Penicillium digitatum. E. coli overexpressing a P450 BM-3 mutant served as biocatalyst to produce several hundreds of milligrams of pinene oxide, verbenol, and myrtenol from α-pinene. Here, an aqueous-organic two-phase bioreactor with diisononylphthalate as organic solvent was used for in situ precursor supply and product recovery.

Renewable resources will be an increasingly important issue for the chemical industry in the future. In the context of white biotechnology, they represent the intersection point of agriculture and the chemical industry. The scarcity and related increase in the price of fossil resources make renewable resources an interesting alternative. If one considers the production of bulk chemicals, it is evident that for this area besides the C sources, sugar and starch, new sources of raw materials must be opened up. One possible solution is to utilize lignocellulose both for materials and energy. This article discusses this interesting prospective for the future, particularly from the point of view of the German industry.

As first steps towards biochemical characterisation we investigated the heterologous production of the plant enzyme carotenoid-cleaving dioxygenase 1 from Aradidopsis thaliana (AtCCD1) in different E. coli hosts and in P. pastoris. An in vitro activity assay for carotenoid-cleaving dioxygenases based on octyl-β-D-glucopyranoside micelles of carotenoids was developed.

The microbial activity of different microorganisms was determined by means of an electrochemical bioactivity sensor (BAS). The BAS is based on a biofuel cell and was used for analytical purposes. Online determination of microbial activity using the BAS demonstrated that when different microorganisms with different metabolic pathways were cultivated, a distinct activity signal was detectable with all organisms applied. Furthermore, the results permitted a quantitative comparison of the BAS signals. Among other findings it was shown that the quotient of the BAS signal and the utilized glucose varied from 0.16-29.08 mV g(-1), the quotient of the maximum BAS signal and the released energy of the reaction exhibited a lower variation of 0.07-0.19 mV kJ(-1). Furthermore it was demonstrated that the highest BAS signals could be measured during anaerobic E. coli fermentations, the reason being the formation of electroactive fermentation products, such as formic acid and H(2).

A novel amperometric sensor system is presented which directly reflects the metabolic activity of prokaryotic and eukaryotic cells during cultivation. The principle of an externally mounted sensor is current measurement using a three-electrode system. Only living cells are detected since the current signal is based on a redox mediator. Added to a culture sample in its oxidized form, the mediator is reduced by cellular metabolism and subsequently re-oxidized at the anode. The spontaneous immobilisation of the cells in the reaction vessel of the sensor by swelling dextrane polymers (Sephadex) prior to measurement is the key to a fast, consistent signal. Even metabolically less active mammalian cells produce a reliable signal within a few minutes; this may open up future applications of the electrochemical sensor in closed loop process control not only for bacterial and fungal bioprocesses, but also in cell culture technology.

The industrial application of biocatalysis for the production of natural flavour compounds is illustrated by a discussion of the production of vanillin, gamma-decalactone, carboxylic acids, C6 aldehydes and alcohols ('green notes'), esters, and 2-phenylethanol. Modern techniques of molecular biology and process engineering, such as heterologous expression of genes, site-directed mutagenesis, whole-cell biocatalysis in biphasic systems, and cofactor regeneration for in vitro oxygenation, may result in more biocatalytic processes for the production of flavour compounds in the future.

2-Phenylethanol (2-PE) is an important flavour and fragrance compound with a rose-like odour. Most of the world's annual production of several thousand tons is synthesised by chemical means but, due to increasing demand for natural flavours, alternative production methods are being sought. Harnessing the Ehrlich pathway of yeasts by bioconversion of L-phenylalanine to 2-PE could be an option, but in situ product removal is necessary due to product inhibition. This review describes the microbial production of 2-PE, and also summarizes the chemical syntheses and the market situation.

Mit einem Bioaktivitatssensor kann die Aktivitat der Mikroorganismen im Belebtschlamm gemessen werden. Das Signal des Sensors reagiert empfindlich auf eine Veranderung des Substratangebots und das Auftreten von toxischen Stoffen. Mit dem Bioaktivitatssensor ist es damit einerseits moglich,online die Belebungsstufe hinsichtlich ihrer mikrobiellen Aktivitat zu kontrollieren und andererseits die zufliesenden Abwasser bezuglich ihres toxischen Potentials zu uberwachen.

An oxygen gas diffusion electrode was successfully used as a cathode in a bioelectro-chemical fuel cell with 2-hydroxy-1,4-naphthoquinone as redox-mediator and Escherichia coli as biocatalyst. On addition of bacteria to the anode compartment of the fuel cell a rapid increase in the electricity output was observed. With the use of a three-dimensional packed bed anode the electricity output of the cell could be considerably increased.