Tailoring non-axenic lactic acid fermentation from cheese whey permeate targeting a flexible lactic acid platform.

Lactic acid (LA) is an important biobased platform chemical, with potential applications in synthetising a wide range of chemical products or serving as feedstock for various bioprocesses. Industrial LA production via pure culture fermentation is characterized by high operational costs and utilizes food-grade sugars, thereby reducing the feasibility of LA applications. In this context, our research focussed on valorising the largest dairy side stream, cheese whey permeate, through the use of mixed microbial communities.

Electrochemical arsenite oxidation for drinking water treatment: Mechanisms, by-product formation and energy consumption.

The mechanisms and by-product formation of electrochemical oxidation (EO) for As(III) oxidation in drinking water treatment using groundwater was investigated. Experiments were carried out using a flowthrough system, with an RuO/IrO MMO Ti anode electrode, fed with synthetic and natural groundwater containing As(III) concentrations in a range of around 75 and 2 µg/L, respectively. Oxidation was dependent on charge dosage (CD) [C/L] and current density [A/m], with the latter showing plateau behaviour for increasing intensity.

The nutritional composition and cell size of microbial biomass for food applications are defined by the growth conditions.

Background: It is increasingly recognized that conventional food production systems are not able to meet the globally increasing protein needs, resulting in overexploitation and depletion of resources, and environmental degradation. In this context, microbial biomass has emerged as a promising sustainable protein alternative. Nevertheless, often no consideration is given on the fact that the cultivation conditions affect the composition of microbial cells, and hence their quality and nutritional value.

Periodic polarization duty cycle tunes performance and adhesion of anodic electroactive biofilms.

Periodic polarization can improve the performance of anodic electroactive biofilms (EABs). The impact of the half-period duration was previously investigated at constant duty cycle (50%), i.e.

Trophic interactions shape the spatial organization of medium-chain carboxylic acid producing granular biofilm communities.

Granular biofilms producing medium-chain carboxylic acids (MCCA) from carbohydrate-rich industrial feedstocks harbor highly streamlined communities converting sugars to MCCA either directly or via lactic acid as intermediate. We investigated the spatial organization and growth activity patterns of MCCA producing granular biofilms grown on an industrial side stream to test (i) whether key functional guilds (lactic acid producing Olsenella and MCCA producing Oscillospiraceae) stratified in the biofilm based on substrate usage, and (ii) whether spatial patterns of growth activity shaped the unique, lenticular morphology of these biofilms. First, three novel isolates (one Olsenella and two Oscillospiraceae species) representing over half of the granular biofilm community were obtained and used to develop FISH probes, revealing that key functional guilds were not stratified.

Continuous cultivation of microalgae yields high nutrient recovery from nitrified urine with limited supplementation.

Microalgae can play a key role in the bioeconomy, particularly in combination with the valorisation of waste streams as cultivation media. Urine is an example of a widely available nutrient-rich waste stream, and alkaline stabilization and subsequent full nitrification in a bioreactor yields a stable nitrate-rich solution. In this study, such nitrified urine served as a culture medium for the edible microalga Limnospira indica.

Microbial protein from recovered nitrogen: Nutritional quality, safety, and feasibility assessment.

In contrast to traditional agriculture, microbial protein (MP) production is highly efficient in nitrogen (N) usage and can be employed to valorize a variety of recovered resources, thereby increasing the overall sustainability of food production. The present study aimed to establish the potential of seven recovered N sources originating from different waste streams for MP production using ethanol and acetate as growth substrates. The evaluation was based on specific growth rate, biomass yield, nutritional quality (i.

Greywater reuse as a key enabler for improving urban wastewater management.

Sustainable water management is essential to guaranteeing access to safe water and addressing the challenges posed by climate change, urbanization, and population growth. In a typical household, greywater, which includes everything but toilet waste, constitutes 50-80% of daily wastewater generation and is characterized by low organic strength and high volume. This can be an issue for large urban wastewater treatment plants designed for high-strength operations.

Comparison of MBR and MBBR followed by UV or electrochemical disinfection for decentralized greywater treatment.

Greywater is an attractive source for water reuse at the household or building level, particularly for non-potable applications. Two greywater treatment approaches are membrane bioreactors (MBR) and moving bed biofilm reactors (MBBR), yet, their performance has not been compared so far within their respective treatment flowsheets, including post-disinfection. Two lab-scale treatment trains were operated on synthetic greywater: a) MBR with either polymeric (chlorinated polyethylene, C-PE, 165 days) or ceramic (silicon carbide, SiC, 199 days) membranes coupled with UV disinfection; and b) single-stage (66 days) or two-stage (124 days) MBBR coupled with an electrochemical cell (EC) for in-situ disinfectant generation.

Steering the product spectrum in high-pressure anaerobic processes: CO partial pressure as a novel tool in biorefinery concepts.

Background: Elevated CO partial pressure (pCO) has been proposed as a potential steering parameter for selective carboxylate production in mixed culture fermentation. It is anticipated that intermediate product spectrum and production rates, as well as changes in the microbial community, are (in)directly influenced by elevated pCO. However, it remains unclear how pCO interacts with other operational conditions, namely substrate specificity, substrate-to-biomass (S/X) ratio and the presence of an additional electron donor, and what effect pCO has on the exact composition of fermentation products.

Electrochemically assisted production of biogenic palladium nanoparticles for the catalytic removal of micropollutants in wastewater treatment plants effluent.

Biogenic palladium nanoparticles (bio-Pd NPs) are used for the reductive transformation and/or dehalogenation of persistent micropollutants. In this work, H (electron donor) was produced in situ by an electrochemical cell, permitting steered production of differently sized bio-Pd NPs. The catalytic activity was first assessed by the degradation of methyl orange.

Transcriptional regulation in key metabolic pathways of Actinobacillus succinogenes in the presence of electricity.

The potential of renewable energy application via direct electrode interaction for the production of bio-based chemicals is a promising technology. The utilization of extracellular energy in pure culture fermentations aims in intracellular redox balance regulation in order to improve fermentation efficiency. This work evaluates the impact of a bioelectrochemical system in succinic acid fermentation and the metabolic response of Actinobacillus succinogenes.

Combined Gold Recovery and Nanoparticle Synthesis in Microbial Systems Using Fractional Factorial Design.

Green synthesis of gold nanoparticles (AuNPs) using microorganisms has been generally studied aiming for high-yield production and morphologies appropriated for various applications, such as bioremediation, (bio)sensors, and (bio)catalysis. Numerous approaches showed the individual effect of factors influencing the synthesis of AuNPs with limited analysis of the governing factors enhancing the production and desired quality of the precipitates. This study proposes a fractional-factorial design to investigate the simultaneous influence of seven environmental factors (cell concentration, temperature, anoxic/oxic conditions, pH, gold concentration, electron donor type, and bacterial species) on the recovery yield and synthesis of targeted AuNPs.

Thermophilic caproic acid production from grass juice by sugar-based chain elongation.

Medium chain carboxylic acids (MCCA) such as caproic acid have a plethora of applications, ranging from food additives to bioplastics. MCCA can be produced via microbial chain elongation using waste and side-streams as substrates, a process that can be more sustainable than conventional production routes. Most chain elongation studies have focused on mesophilic conditions, with only two recent studies hinting at the possibility of thermophilic chain elongation, but a systematic study of its mechanisms is lacking.

Microbial electrosynthesis of acetate from CO under hypersaline conditions.

Microbial electrosynthesis (MES) enables the bioproduction of multicarbon compounds from CO using electricity as the driver. Although high salinity can improve the energetic performance of bioelectrochemical systems, acetogenic processes under elevated salinity are poorly known. Here MES under 35-60 g L salinity was evaluated.

How can we possibly resolve the planet's nitrogen dilemma?

Nitrogen is the most crucial element in the production of nutritious feeds and foods. The production of reactive nitrogen by means of fossil fuel has thus far been able to guarantee the protein supply for the world population. Yet, the production and massive use of fertilizer nitrogen constitute a major threat in terms of environmental health and sustainability.

The Role of Microorganisms and Carbon-to-Nitrogen Ratios for Microbial Protein Production from Bioethanol.

With industrial agriculture increasingly challenging our ecological limits, alternative food production routes such as microbial protein (MP) production are receiving renewed interest. Among the multiple substrates so far evaluated for MP production, renewable bioethanol (EtOH) is still underexplored. Therefore, the present study investigated the cultivation of five microorganisms (2 bacteria, 3 yeasts) under carbon (C), nitrogen (N), and dual C-N-limiting conditions (molar C/N ratios of 5, 60, and 20, respectively) to evaluate the production (specific growth rate, protein and biomass yield, production cost) as well as the nutritional characteristics (protein and carbohydrate content, amino acid [AA] profile) of MP production from bioethanol.

Accelerating urea hydrolysis in fresh urine by modifying operating conditions of a sequencing batch reactor.

A number of existing and emerging technologies can recover nitrogen from urine. A preliminary step in many nitrogen recovery processes is hydrolyzing urea to ammonium, a biologically-mediated process that can take days to weeks without intervention. The ability to achieve urea hydrolysis quickly and reliably would increase the feasibility of decentralized nitrogen recovery, especially where space and treatment time are constrained.

In silico assessment of household level closed water cycles: Towards extreme decentralization.

Water management in most of the developed world is currently practiced in a highly centralized manner, leading to major infrastructure and energy costs to transport water. To decrease the impacts of water scarcity and climate change, the decentralization of water can increase local robustness. In extremis, decentralization can involve building or house level water supply and treatment.

High rate production of concentrated sulfides from metal bearing wastewater in an expanded bed hydrogenotrophic sulfate reducing bioreactor.

Metallurgical wastewaters contain high concentrations of sulfate, up to 15 g L. Sulfate-reducing bioreactors are employed to treat these wastewaters, reducing sulfates to sulfides which subsequently co-precipitate metals. Sulfate loading and reduction rates are typically restricted by the total HS concentration.

Lignocellulose Fermentation Products Generated by Giant Panda Gut Microbiomes Depend Ultimately on pH Rather than Portion of Bamboo: A Preliminary Study.

Giant pandas feed almost exclusively on bamboo but miss lignocellulose-degrading genes. Their gut microbiome may contribute to their nutrition; however, the limited access to pandas makes experimentation difficult. In vitro incubation of dung samples is used to infer gut microbiome activity.