Publications by authors named "Tonanzi Barbara"

The biochemical valorization potential of food waste (FW) could be exploited by extracting decreasing added-value bio-based products and converting the final residues into energy. In this context, multi-purpose and versatile schemes integrating thermal and biochemical conversion processes will play a key role. An upstream thermal pretreatment + solid-liquid separation unit was here proposed to optimize the conversion of the liquid fraction of FW into valuable chemicals through semi-continuous fermentation process, and the conversion of the residual solid fraction into biomethane through anaerobic digestion.

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Marine sediments act as a sink for the accumulation of various organic contaminants such as polychlorobiphenyls (PCBs). These contaminants affect the composition and activity of microbial communities, particularly favoring those capable of thriving from their biodegradation and biotransformation under favorable conditions. Hence, contaminated environments represent a valuable biological resource for the exploration and cultivation of microorganisms with bioremediation potential.

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Microbial chain elongation has emerged as a valuable bioprocess for obtaining marketable products, such as medium chain fatty acids usable in several industrial applications, from organic waste. The understanding of the microbiology and microbial ecology in these systems is crucial to apply these microbiomes in reliable production processes controlling microbial pathways to promote favourable metabolic processes, which will in turn increase product specificity and yields. In this research, the dynamics, cooperation/competition and potentialities of bacterial communities involved in the long-term lactate-based chain elongation process from food waste extract were evaluated under different operating conditions by DNA/RNA amplicon sequencing and functional profile prediction.

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Article Synopsis
  • The European Green Deal aims to promote sustainable practices, with new technologies and renewable resources being critical for advancing a bio-based economy, including converting food waste into valuable products like carboxylic acids through fermentation.
  • This study focuses on producing caproate from organic-rich food waste extract using an in situ electron donor, achieving significant yields of volatile fatty acids and a maximum caproate concentration of 8 g/L under optimal conditions.
  • However, increasing the organic loading rate (OLR) to 20 gCOD Ld inhibited the chain elongation process due to high caproate concentrations, but the system recovered its functionality after a brief pause in feeding, indicating a resilient microbiome's ability
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Over the last years, in a search for sustainable and biodegradable alternatives to petrol-based plastics, biotechnological applications turned to the potentialities of mixed microbial cultures (MMC) for producing polyhydroxyalkanoates (PHAs). Under a feast and famine regime, an uncoupled carbon (C) and nitrogen (N)-feeding strategy may be adopted by dosing the C-source at the beginning of the feast and the N-source at the beginning of the famine in order to stimulate a PHA storage response and microbial growth. Even though this strategy has been already successfully applied for the PHA production, very few information is to date available regarding the MMC operating in these systems and the influence of Organic Loading Rate (OLR) on their selection and enrichment.

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  • Anaerobic digestion is an established method for stabilizing sewage sludge and producing biogas, but there's limited knowledge about the microbial changes during the initial start-up phase of digesters.
  • This study examined the bacterial and archaeal populations in a full-scale mesophilic digester from start-up to steady-state using high-throughput DNA sequencing, revealing a predominance of fermentative bacteria and specific methanogens that adapted over time.
  • The research highlighted which microbial communities are most affected by changes from aerobic to anaerobic conditions and assessed the core microbial populations influenced by the wastewater treatment plant's operational parameters.
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The amount of sewage sludge generated from wastewater treatment plants globally is unavoidably increasing. In recent years, significant attention has been paid to the biorefinery concept based on the conversion of waste streams to high-value products, material, and energy by microorganisms. However, one of the most significant challenges in the field is the possibility of controlling the microorganisms' pathways in the anaerobic environment.

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A novel biorefinery platform integrating thermal pretreatment and solid-liquid separation unit is here proposed to fully exploit food waste (FW) potential for production of valuable chemicals and energy through semi-continuous anaerobic bioconversion. The liquid fraction deriving from raw or pretreated FW, was fermented into volatile fatty acids (VFAs, from acetic to caproic acid) while the residual fraction was converted into biomethane. Thermal pretreatment effectively extracted a portion of the macromolecular organics, especially starch, to the liquid phase, promoting acidogenic fermentation and chain elongation pathways (0.

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Anaerobic digestion is applied worldwide to treat food waste (FW) with the aim of obtaining renewable bioenergy by exploiting the methane gas produced. However, there are several problems in practical applications, primarily due to system instability. Although exhaustive knowledge regarding anaerobic microbial community composition has been established, few studies have investigated long-term correlations between microbial consortia, operative conditions and feedstock characteristics.

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The reasons for the acidification problem affecting Food Waste (FW) anaerobic digestion were explored, combining the outcomes of microbiological data (FISH and CARD-FISH) and process modelling, based on the Anaerobic Digestion Model n°1 (ADM1). Long term semi continuous experiments were carried out, both with sole FW and with Waste Activated Sludge (WAS) as a co-substrate, at varying operational conditions (0.8-2.

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Article Synopsis
  • The study investigates a mixed microbial community (MMC) in a pilot plant that produces polyhydroxyalkanoate (PHA) from organic waste and sewage sludge.
  • The research utilizes high-throughput sequencing of the 16S rRNA gene to identify various PHA-accumulating bacteria that maintain stable PHA production despite fluctuations in volatile fatty acids (VFAs) and temperature.
  • The findings highlight that the highest PHA content is linked to a community dominated by Hydrogenophaga species, showcasing functional redundancy within the diverse PHA-accumulating bacteria present.
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