Pilot-scale chitin extraction from shrimp shell waste by deproteination and decalcification with bacterial enrichment cultures.

Extraction of chitin from mechanically pre-purified shrimp shells can be achieved by successive NaOH/HCl treatment, protease/HCl treatment or by environmentally friendly fermentation with proteolytic/lactic acid bacteria (LAB). For the last mentioned alternative, scale-up of shrimp shell chitin purification was investigated in 0.25 L (F1), 10 L (F2), and 300 L (F3) fermenters using an anaerobic, chitinase-deficient, proteolytic enrichment culture from ground meat for deproteination and a mixed culture of LAB from bio-yoghurt for decalcification.

Co-digestion of wheat and rye bread suspensions with source-sorted municipal biowaste.

Acidification of wheat bread (WBS), rye bread (RBS) and fresh biowaste suspensions (FBS), leading to lactate+acetate, lactate+acetate+n-buyrate, and acetate+propionate+n-butyrate, respectively, and biogas production as well as population dynamics were investigated. Co-fermentation of FBS (14 kg m(-3) d(-1) organic loading rate (OLR)) with WBS or RBS was stable up to an OLR of 22 kg m(-3) d(-1) and resulted in up to 3 times as much biogas. During co-fermentation at more than 20 kg m(-3) d(-1) OLR the total population increased more than 2-fold, but the originally low share of propionate-oxidizing bacteria significantly decreased.

Microbial Community Shifts during Biogas Production from Biowaste and/or Propionate.

Propionate is the most delicate intermediate during anaerobic digestion as its degradation is thermodynamically unfavorable. To determine its maximum possible degradation rates during anaerobic digestion, a reactor was fed Monday to Friday with an organic loading rate (OLR) of 12/14 kg COD·m·d plus propionate up to a final OLR of 18 kg COD·m·d. No feed was supplied on weekends as it was the case in full-scale.

Removal of total and antibiotic resistant bacteria in advanced wastewater treatment by ozonation in combination with different filtering techniques.

Elimination of bacteria by ozonation in combination with charcoal or slow sand filtration for advanced sewage treatment to improve the quality of treated sewage and to reduce the potential risk for human health of receiving surface waters was investigated in pilot scale at the sewage treatment plant Eriskirch, Baden-Wuerttemberg/Germany. To determine the elimination of sewage bacteria, inflowing and leaving wastewater of different treatment processes was analysed in a culture-based approach for its content of Escherichia coli, enterococci and staphylococci and their resistance against selected antibiotics over a period of 17 month. For enterococci, single species and their antibiotic resistances were identified.

Se (IV) triggers faster Te (IV) reduction by soil isolates of heterotrophic aerobic bacteria: formation of extracellular SeTe nanospheres.

Background: Selenium and Tellurium have many common chemical properties as both belong to group 16 of the periodic table. High toxicities of Se and Te oxyanions cause environmental problems in contaminated soils and waters. Three strains (C4, C6 and C7) of selenite reducing and nanoparticle forming aerobic bacteria which were isolated from agricultural soils of India containing high concentrations of Se were investigated after 3.

Fatty acid metabolism and population dynamics in a wet biowaste digester during re-start after revision.

Volatile fatty acid (VFA) metabolism and population changes during re-start of a wet anaerobic digester for treatment of biowaste suspensions were investigated. Initially acetate and propionate accumulated. However, VFA degradation rates improved within 2 weeks, reaching a balanced metabolism with constantly low VFA concentrations.

Effect of moisture of municipal biowaste on start-up and efficiency of mesophilic and thermophilic dry anaerobic digestion.

Methane production from biowaste with 20-30% dry matter (DM) by box-type dry anaerobic digestion and contributing bacteria were determined for incubation at 20, 37 and 55 °C. The same digestion efficiency as for wet anaerobic digestion of biowaste was obtained for dry anaerobic digestion with 20% DM content at 20, 37 and 55 °C and with 25% DM content at 37 and 55 °C. No or only little methane was produced in dry anaerobic reactors with 30% DM at 20, 37 or 55 °C.

Transformation of the matrix structure of shrimp shells during bacterial deproteination and demineralization.

Background: After cellulose and starch, chitin is the third-most abundant biopolymer on earth. Chitin or its deacetylated derivative chitosan is a valuable product with a number of applications. It is one of the main components of shrimp shells, a waste product of the fish industry.

Biogas and biohydrogen production potential of high strength automobile industry wastewater during anaerobic degradation.

High strength automobile industry wastewater, collected from decanters (DECA) of the pre-treatment plant after oil, grease and sludge separation, was investigated for production of methane in the absence and presence of glucose or excess aerobic sludge (AS) from a lab scale suspension reactor as co-substrates. The highest methane production from DECA wastewater was 335.4 L CH4/kg CODsoluble removal which decreased in the presence of the co-substrates to 232.

Effect of carbon sources and of sulfate on microbial arsenic mobilization in sediments of West Bengal, India.

Arsenic (As) dissolution from sediments into groundwater in the Bengal Delta/West India was investigated. Two experimental sites were choosen with contrasting As concentrations in shallow groundwater. Apparently patches of high-As and low-As sediments occured in close neigbourhood.

Influences of groundwater extraction on the distribution of dissolved As in shallow aquifers of West Bengal, India.

Here we report temporal changes of As concentrations in shallow groundwater of the Bengal Delta Plain (BDP). Observed fluctuations are primarily induced by seasonally occurring groundwater movement, but can also be connected to anthropogenic groundwater extraction. Between December 2009 and July 2010, pronounced variations in the groundwater hydrochemistry were recorded in groundwater samples of a shallow monitoring well tapping the aquifer in 22-25 m depth, where Astot concentrations increased within weeks from 100 to 315 μg L(-1).

Interspecies distances between propionic acid degraders and methanogens in syntrophic consortia for optimal hydrogen transfer.

A mixed culture from an anaerobic biowaste digester was enriched on propionate and used to investigate interspecies hydrogen transfer in dependence of spatial distances between propionate degraders and methanogens. From 20.3 mM propionate, 20.

Long-term effects of antibiotics on the elimination of chemical oxygen demand, nitrification, and viable bacteria in laboratory-scale wastewater treatment plants.

Antibiotics and other pharmaceuticals are contaminants of the environment because of their widespread use and incomplete removal by microorganisms during wastewater treatment. The influence of a mixture of ciprofloxacin (CIP), gentamicin (GM), sulfamethoxazole (SMZ)/trimethoprim (TMP), and vancomycin (VA), up to a final concentration of 40 mg/L, on the elimination of chemical oxygen demand (COD), nitrification, and survival of bacteria, as well as the elimination of the antibiotics, was assessed in a long-term study in laboratory treatment plants (LTPs). In the presence of 30 mg/L antibiotics, nitrification of artificial sewage by activated sludge ended at nitrite.

Formation of Se (0) nanoparticles by Duganella sp. and Agrobacterium sp. isolated from Se-laden soil of North-East Punjab, India.

Background: Selenium (Se) is an essential trace element, but is toxic at high concentrations. Depending upon the geological background, the land use or on anthropogenic pollution, different amounts of Se may be present in soil. Its toxicity is related to the oxyanions selenate and selenite as they are water soluble and bioavailable.

Mass spectrometric identification of 13C-labeled metabolites during anaerobic propanoic acid oxidation.

Biowaste digestion is a possibility to gain biogas as a renewable fuel source. However, the anaerobic food chain may be disrupted by, e.g.

Genotyping of environmental and clinical Stenotrophomonas maltophilia isolates and their pathogenic potential.

Stenotrophomonas maltophilia is a highly versatile species with useful biotechnological potential but also with pathogenic properties. In light of possible differences in virulence characteristics, knowledge about genomic subgroups is therefore desirable. Two different genotyping methods, rep-PCR fingerprinting and partial gyrB gene sequencing were used to elucidate S.

Hazardous concentrations of selenium in soil and groundwater in North-West India.

Soil and groundwater samples were collected for bulk elemental analyses in particular for selenium (Se) concentrations from six agricultural sites located in states of Punjab and Haryana in North-West India. Toxic concentrations of Se (45-341 μg L(-1)) were present in groundwater (76 m deep) of Jainpur and Barwa villages in Punjab. Selenium enrichments were also found in top soil layers (0-15 cm) of Jainpur (2.

Hydrogen formation by an arsenate-reducing Pseudomonas putida, isolated from arsenic-contaminated groundwater in West Bengal, India.

Anaerobic growth of a newly isolated Pseudomonas putida strain WB from an arsenic-contaminated soil in West Bengal, India on glucose, L: -lactate, and acetate required the presence of arsenate, which was reduced to arsenite. During aerobic growth in the presence of arsenite arsenate was formed. Anaerobic growth of P.

Co-digestion of press water and food waste in a biowaste digester for improvement of biogas production.

Co-digestion of press water from organic municipal wastes and of homogenized food residues with defibered kitchen wastes (food waste) as the main substrate was examined to improve biogas production. Although the biowaste digester was operated already at high organic loading (OLR) of 12.3 kg CODm(-3)d(-1) during the week, addition of co-substrates not only increased biogas production rates but also improved total biogas production.

Effect of phenol addition on COD and nitrate removal in an anoxic suspension reactor.

In this study, a denitrifying culture was enriched in a continuously re-circulated anoxic suspension reactor fed with glucose and nitrate for about 8 months (stage I) under different organic loading rates (OLR). At the end of stage I, the removal efficiency for NO(3)(-)-N was 80% with 93% COD (5 g/l) removal at an OLR of 2.5 g/ld.

Distribution of aerobic motile and non-motile bacteria within the capillary fringe of silica sand.

Retention of bacterial cells as "particles" by silica sand during formation of a capillary fringe (CF) and the influence of motility was examined with motile Pseudomonas putida and non-motile Corynebacterium glutamicum suspensions in the absence of nutrients. The fractional retention of C. glutamicum cells at all regions of the CF was higher than for P.

Nitrification in fixed-bed reactors treating saline wastewater.

Halophilic nitrifiers belonging to the genus Nitrosomonas and Nitrospira were enriched from seawater and marine sediment samples of the North Sea. The maximal ammonia oxidation rate (AOR) in batch enrichments with seawater was 15.1 mg N L(-1) day(-1).

Anaerobic digestion of pressed off leachate from the organic fraction of municipal solid waste.

A highly polluted liquid ("press water") was obtained from the pressing facility for the organic fraction of municipal solid waste in a composting plant. Methane productivity of the squeezed-off leachate was investigated in batch assays. To assess the technical feasibility of "press water" as a substrate for anaerobic digestion, a laboratory-scale glass column reactor was operated semi-continuously at 37 degrees C.

Foodwaste as a co-substrate in a fed-batch anaerobic biowaste digester for constant biogas supply.

The use of foodwaste as a supplementary substrate for an anaerobic municipal biowaste digester during night times and as the sole substrate during weeks ends, when no biowaste suspension was available was studied in order to equilibrate biogas production. Assays were performed in semi-continuously fed laboratory reactors with real substrates, simulating practical feed conditions. Biogas production of biowaste or foodwaste reached 0.

Anaerobic biodegradation of high strength 2-chlorophenol-containing synthetic wastewater in a fixed bed reactor.

In this study the continuous treatment of 2-chlorophenol (2-CP) containing synthetic wastewater at increasing concentrations up to 2600 mg L-1 in an anaerobic fixed bed reactor was achieved. As a source of microorganisms municipal sewage sludge was acclimatised to maximally 50 mg L-1 2-CP by 3 successive feedings within 1.5 months.