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Diversity and metabolism of xylose and glucose fermenting microbial communities in sequencing batch or continuous culturing

Rombouts, J.L. (author), Mos, G. (author), Weissbrodt, D.G. (author), Kleerebezem, R. (author), van Loosdrecht, Mark C.M. (author)

A mechanistic understanding of microbial community establishment and product formation in open fermentative systems can aid the development of bioprocesses utilising organic waste. Kinetically, a single rate-limiting substrate is expected to result in one dominant species. Four enrichment cultures were operated to ferment either xylose or...

journal article 2019

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O₂ versus N₂O respiration in a continuous microbial enrichment

Conthe Calvo, M. (author), Parchen, C.M. (author), Stouten, G.R. (author), Kleerebezem, R. (author), van Loosdrecht, Mark C.M. (author)

Despite its ecological importance, essential aspects of microbial N₂O reduction—such as the effect of O₂ availability on the N₂O sink capacity of a community—remain unclear. We studied N₂O vs. aerobic respiration in a chemostat culture to explore (i) the extent to which simultaneous respiration of N...

journal article 2018

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Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities

Junicke, H. (author), Van Loosdrecht, M.C.M. (author), Kleerebezem, R. (author)

Many anaerobic conversions proceed close to thermodynamic equilibrium and the microbial groups involved need to share their low energy budget to survive at the thermodynamic boundary of life. This study aimed to investigate the kinetic and thermodynamic control mechanisms of the electron transfer during syntrophic butyrate conversion in non...

journal article 2015

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Anaerobic digestion without biogas?

Kleerebezem, R. (author), Joosse, B. (author), Rozendaal, R. (author), Van Loosdrecht, M.C.M. (author)

Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the production of a single end-product from a...

journal article 2015

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Influence of silicate on enrichment of highly productive microalgae from a mixed culture

Mooij, P.R. (author), De Jongh, L.D. (author), Van Loosdrecht, M.C.M. (author), Kleerebezem, R. (author)

Microalgae have the potential to supply a biobased society with essential feedstocks like sugar and lipids. Besides being productive, strains used for this purpose should grow fast, be resistant to predators, and have good harvestability properties. Diatoms, a class of siliceous algae, have these and other preferred characteristics. In this...

journal article 2015

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Effect of sludge age on methanogenic and glycogen accumulating organisms in an aerobic granular sludge process fed with methanol and acetate

Pronk, M. (author), Abbas, B. (author), Kleerebezem, R. (author), Van Loosdrecht, M.C.M. (author)

The influence of sludge age on granular sludge formation and microbial population dynamics in a methanol- and acetate-fed aerobic granular sludge system operated at 35°C was investigated. During anaerobic feeding of the reactor, methanol was initially converted to methane by methylotrophic methanogens. These methanogens were able to withstand...

journal article 2015

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Physiological and Transcriptional Responses of Different Industrial Microbes at Near-Zero Specific Growth Rates

Ercan, O. (author), Bisschops, M.M. (author), Overkamp, W. (author), Jørgensen, T.R. (author), Rama, A.F. (author), Smid, E.J. (author), Pronk, J.T. (author), Kuipers, O.P. (author), Daran-Lapujade, P. (author), Kleerebezem, M. (author)

The current knowledge of the physiology and gene expression of industrially relevant microorganisms is largely based on laboratory studies under conditions of rapid growth and high metabolic activity. However, in natural ecosystems and industrial processes, microbes frequently encounter severe calorie restriction. As a consequence, microbial...

journal article 2015

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Storage compound production by phototrophic diatoms

Mooij, P.R. (author), Van Loosdrecht, M.C.M. (author), Kleerebezem, R. (author)

The invention is directed to a method for producing an enriched diatom culture, comprising subjecting a starting culture comprising one or more diatom species to selective pressure, thus giving a competitive advantage to storage compound producing species of diatoms, by subjecting said starting culture, under non-limiting bioavailable silicon...

patent 2015

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Lipid recovery from a vegetable oil emulsion using microbial enrichment cultures

Tamis, J. (author), Sorokin, D.Y. (author), Jiang, Y. (author), Van Loosdrecht, M.C.M. (author), Kleerebezem, R. (author)

Background Many waste streams have a relatively high vegetable oil content, which is a potential resource that should be recovered. Microbial storage compound production for the recovery of lipids from lipid-water emulsions with open (unsterilized) microbial cultures was investigated in a sequencing batch reactor using a diluted vegetable oil...

journal article 2015

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Genome-Wide Transcriptional Responses to Carbon Starvation in Nongrowing Lactococcus lactis

Ercan, O. (author), Wels, M. (author), Smid, E.J. (author), Kleerebezem, M. (author)

This paper describes the transcriptional adaptations of nongrowing, retentostat cultures of Lactococcus lactis to starvation. Near-zero-growth cultures (? = 0.0001 h?1) obtained by extended retentostat cultivation were exposed to starvation by termination of the medium supply for 24 h, followed by a recovery period of another 24 h by...

journal article 2015

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Molecular and Metabolic Adaptations of Lactococcus lactis at Near-Zero Growth Rates

Ercan, O. (author), Wels, M. (author), Smid, E.J. (author), Kleerebezem, M. (author)

This paper describes the molecular and metabolic adaptations of Lactococcus lactis during the transition from a growing to a near-zero growth state by using carbon-limited retentostat cultivation. Transcriptomic analyses revealed that metabolic patterns shifted between lactic- and mixed-acid fermentations during retentostat cultivation, which...

journal article 2015

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Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture

Jiang, Y. (author), Mikova, G. (author), Kleerebezem, R. (author), Van der Wielen, L.A.M. (author), Cuellar Soares, M.C. (author)

This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS (0.2 w/v% SDS) could reach 99% purity, with more...

journal article 2015

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Effect and behaviour of different substrates in relation to the formation of aerobic granular sludge

Pronk, M. (author), Abbas, B. (author), Al-zuhairy, S.H.K. (author), Kraan, R. (author), Kleerebezem, R. (author), Van Loosdrecht, M.C.M. (author)

When aerobic granular sludge is applied for industrial wastewater treatment, different soluble substrates can be present. For stable granular sludge formation on volatile fatty acids (e.g. acetate), production of storage polymers under anaerobic feeding conditions has been shown to be important. This prevents direct aerobic growth on readily...

journal article 2015

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Absolute Quantification of Individual Biomass Concentrations in a Methanogenic Coculture

Junicke, H. (author), Abbas, B. (author), Oentoro, J. (author), Van Loosdrecht, M. (author), Kleerebezem, R. (author)

Identification of individual biomass concentrations is a crucial step towards an improved understanding of anaerobic digestion processes and mixed microbial conversions in general. The knowledge of individual biomass concentrations allows for the calculation of biomass specific conversion rates which form the basis of anaerobic digestion models....

journal article 2014

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GtfA and GtfB Are Both Required for Protein O-Glycosylation in Lactobacillus plantarum

Lee, I.C. (author), Van Swam, I.I. (author), Tomita, S. (author), Morsomme, P.D. (author), Rolain, T. (author), Hols, P. (author), Kleerebezem, M. (author), ron, P.A. (author)

Acm2, the major autolysin of Lactobacillus plantarum WCFS1, was recently found to be O-glycosylated with N-acetylhexosamine, likely N-acetylglucosamine (GlcNAc). In this study, we set out to identify the glycosylation machinery by employing a comparative genomics approach to identify Gtf1 homologues, which are involved in fimbria-associated...

journal article 2014

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H2O2 Production in Species of the Lactobacillus acidophilus Group: A Central Role for a Novel NADH-Dependent Flavin Reductase

Hertzberger, R. (author), Arents, J. (author), Dekker, H.L. (author), Pridmore, D. (author), Gysler, C. (author), Kleerebezem, M. (author), Teixeira de Mattosa, M.J. (author)

Hydrogen peroxide production is a well-known trait of many bacterial species associated with the human body. In the presence of oxygen, the probiotic lactic acid bacterium Lactobacillus johnsonii NCC 533 excretes up to 1 mM H2O2, inducing growth stagnation and cell death. Disruption of genes commonly assumed to be involved in H2O2 production (e...

journal article 2014

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Method for obtaining an open phototrophic culture with improved storage compound production capacity

Tamis, J. (author), Kleerebezem, R. (author), Van Loosdrecht, M.C.M. (author)

The invention is directed to a method for producing an open phototrophic culture with improved storage compound production capability. In accordance with the invention, a starting culture is submitted to selective pressure, thus giving a competitive advantage to storage compound producing species, by subjecting said starting culture to a cycle...

patent 2013

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Metabolic modeling of denitrification in Agrobacterium tumefaciens: A tool to study inhibiting and activating compounds for the denitrification pathway

Kampschreur, M.J. (author), Kleerebezem, R. (author), Picioreanu, C. (author), Bakken, L. (author), Bergaust, L. (author), De Vries, S. (author), Jetten, M.S.M. (author), Van Loosdrecht, M.C.M. (author)

A metabolic network model for facultative denitrification was developed based on experimental data obtained with Agrobacterium tumefaciens. The model includes kinetic regulation at the enzyme level and transcription regulation at the enzyme synthesis level. The objective of this work was to study the key factors regulating the metabolic response...

journal article 2012

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Metabolic modeling of denitrification in Agrobacterium tumefaciens: A tool to study inhibiting and activating compounds for the denitrification pathway

Kampschreur, M.J. (author), Kleerebezem, R. (author), Picioreanu, C. (author), Bakken, L. (author), Bergaust, L. (author), De Vries, S. (author), Jetten, M.S.M. (author), Van Loosdrecht, M.C.M. (author)

journal article 2012

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Unravelling the reasons for disproportion in the ratio of AOB and NOB in aerobic granular sludge

Winkler, M.K.H. (author), Bassin, J.P. (author), Kleerebezem, R. (author), Sorokin, D.Y. (author), Van Loosdrecht, M.C.M. (author)

In this study, we analysed the nitrifying microbial community (ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB)) within three different aerobic granular sludge treatment systems as well as within one flocculent sludge system. Granular samples were taken from one pilot plant run on municipal wastewater as well as from two...

journal article 2012