Intracranial Phosphaturic Mesenchymal Tumors: A Systematic Literature Review of a Rare Entity.

BACKGROUND: Phosphaturic Mesenchymal Tumors (PMTs) are rare mesenchymal neoplasms known for producing Tumor-induced Osteomalacia (TIO). TIO is an uncommon paraneoplastic syndrome characterized by radiographic evidence of inadequate bone mineralization and analytical abnormalites. METHODS: We sought to present a case of TIO caused by skull base PMT with intracranial extension, manifesting with pain, progressive weakness, and multiple bone fractures. Furthermore, a systematic review was performed, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A search was conducted in PubMed database with title/abstract keywords "Phosphaturic mesenchymal tumor" and "Osteomalacia." Search results were reviewed looking for intracranial or skull base tumors. RESULTS: Our systematic review included 29 reported cases of intracranial PMT. In the reviewed cases there was a significative female predominance with 22 cases (75,86%). Osteomalacia was presented in 25 cases (86,20%). Bone fractures were present in 10 cases (34,48%). The most common site of involvement was the anterior cranial fossa in 14 cases (48,27%). Surgery was performed in 27 cases (93,10%) with previous tumor embolization in 4 cases (13,79%). Total recovery of the presenting symptoms in the first year was achieved in 21 cases (72,41%). Recurrence of the disease was described in 6 cases (25%). CONCLUSIONS: Skull base PMTs with intracranial extension are extremely rare tumors. Most patients are middle-aged adults with a PMT predominantly located in anterior cranial fossa. Surgery is the current treatment of choice with optimal outcome at 1-year follow-up, although recurrence could be present in almost 25% of the cases.

Production of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from methane and volatile fatty acids: properties, metabolic routes and current trend.

Polyhydroxyalkanoates (PHAs) are biobased and biodegradable polymers that could effectively replace fossil-based and non-biodegradable plastics. However, their production is currently limited by the high production costs, mainly due to the costly carbon sources used, low productivity and quality of the materials produced. A potential solution lies in utilizing cheap and renewable carbon sources as the primary feedstock during the biological production of PHAs, paving the way for a completely sustainable and economically viable process. In this review, the opportunities and challenges related to the production of polyhydroxyalkanoates using methane and volatile fatty acids (VFAs) as substrates were explored, with a focus on poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). The discussion reports the current knowledge about promising Type II methanotrophs, the impact of process parameters such as limiting nutrients, CH4:O2 ratio and temperature, the type of co-substrate and its concentration. Additionally, the strategies developed until now to enhance PHA production yields were also discussed.

Polyhydroxyalkanoate recovery overview: properties, characterizations, and extraction strategies.

Due to their excellent properties, polyhydroxyalkanoates are gaining increasing recognition in the biodegradable polymer market. These biogenic polyesters are characterized by high biodegradability in multiple environments, overcoming the limitation of composting plants only and their versatility in production. The most consolidated techniques in the literature or the reference legislation for the physical, chemical and mechanical characterisation of the final product are reported since its usability on the market is still linked to its quality, including the biodegradability certificate. This versatility makes polyhydroxyalkanoates a promising prospect with the potential to replace fossil-based thermoplastics sustainably. This review analyses and compares the physical, chemical and mechanical properties of poly-ß-hydroxybutyrate and poly-ß-hydroxybutyrate-co-ß-hydroxyvalerate, indicating their current limitations and strengths. In particular, the copolymer is characterised by better performance in terms of crystallinity, hardness and workability. However, the knowledge in this area is still in its infancy, and the selling prices are too high (9-18 $ kg-1). An analysis of the main extraction techniques, established and in development, is also included. Solvent extraction is currently the most widely used method due to its efficiency and final product quality. In this context, the extraction phase of the biopolymer production process remains a major challenge due to its high costs and the need to use non-halogenated toxic solvents to improve the production of good-quality bioplastics. The review also discusses all fundamental parameters for optimising the process, such as solubility and temperature.

Techno-economic assessment of biopolymer production from methane and volatile fatty acids: effect of the reactor size and biomass concentration on the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) selling price.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is a biobased and biodegradable polymer that could efficiently replace fossil-based plastics. However, its widespread deployment is slowed down by the high production cost. In this work, the techno-economic assessment of the process for producing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from low-cost substrates, such as methane and valeric acid derived from the anaerobic digestion of organic wastes, is proposed. Several strategies for cost abatement, such as the use of a mixed consortium and a line for reagent recycling during downstream, were adopted. Different scenarios in terms of production, from 100 to 100,000 t/y, were analysed, and, for each case, the effect of the reactor volume (small, medium and large size) on the selling price was assessed. In addition, the effect of biomass concentration was also considered. Results show that the selling price of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is minimum for a production plant with 100,000 t/y capacity, accounting for 18.4 €/kg, and highly influenced by the biomass concentration since it can be reduced up to 8.6 €/kg by increasing the total suspended solids from 5 to 30 g/L, This adjustment aligns the breakeven point of PHBV with the reported average commercial price.

Exploring New Strategies for Optimizing the Production of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from Methane and VFAs in Synthetic Cocultures and Mixed Methanotrophic Consortia.

In this work, the potential of a synthetic coculture and a mixed methanotrophic consortium to synthesize poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from renewable and waste-based feedstocks was assessed batchwise. Methylocystis parvuscocultivated with Rhodococcus opacus and a Methylocystis-enriched culture previously grown on methane were subjected to nutrient starvation in a medium enriched with valeric acid (30% w w-1 of Ctot) or with a VFAs mixture containing acetic, propionic, butyric, and valeric acids (15% w w-1 of Ctot) under a CH4:O2 or air atmosphere. For all test series, pH was adjusted to 7 after adding the cosubstrates, and a negligible substrate consumption or polymer production was considered the end point of the trial. Results showed that valeric acid promoted PHBV accumulation in both cultures regardless of the atmosphere. Interestingly, the mixture of VFAs supported PHBV accumulation only in the presence of methane. The highest PHBV contents for the coculture and the mixed consortium, equal to 73.7 ± 2.5% w w-1 and 49.6 ± 13% w w-1, respectively, were obtained with methane and the VFAs mixture. This study demonstrates the suitability of cocultures and biobased cosubstrates for the sustainable production of the biodegradable polymer PHBV.

Enrichment of a mixed syngas-converting culture for volatile fatty acids and methane production.

The present study evaluated the production potential of CH4, carboxylic acids and alcohols from a mixed culture enriched using synthetic syngas. The influence of syngas concentration on the microbial community and products productivity and selectivity was investigated. The results demonstrated the enrichment of a mesophilic mixed culture capable of converting CO and H2 mainly to CH4 and acetate, along with butyrate. The selectivity values showed that acetate production was enhanced during the first cycle in all conditions tested (up to 20 %), while CH4 was the main product generated during following cycles. Concretely, CH4 selectivity remained unaffected by syngas concentration, reaching a stable value of 41.6 ± 2.0 %. On the other hand, butyrate selectivity was only representative at the highest syngas concentration and lower pH values (26.1 ± 5.8 %), where the H2 consumption was completely inhibited. Thus, pH was identified as a key parameter for both butyrate synthesis and the development of hydrogenotrophic activity.

Genome-scale metabolic model of the versatile bacterium Paracoccus denitrificans Pd1222.

A genome scale metabolic model of the bacterium Paracoccus denitrificans has been constructed. The model containing 972 metabolic genes, 1,371 reactions, and 1,388 unique metabolites has been reconstructed. The model was used to carry out quantitative predictions of biomass yields on 10 different carbon sources under aerobic conditions. Yields on C1 compounds suggest that formate is oxidized by a formate dehydrogenase O, which uses ubiquinone as redox co-factor. The model also predicted the threshold methanol/mannitol uptake ratio, above which ribulose biphosphate carboxylase has to be expressed in order to optimize biomass yields. Biomass yields on acetate, formate, and succinate, when NO3- is used as electron acceptor, were also predicted correctly. The model reconstruction revealed the capability of P. denitrificans to grow on several non-conventional substrates such as adipic acid, 1,4-butanediol, 1,3-butanediol, and ethylene glycol. The capacity to grow on these substrates was tested experimentally, and the experimental biomass yields on these substrates were accurately predicted by the model.IMPORTANCEParacoccus denitrificans has been broadly used as a model denitrifying organism. It grows on a large portfolio of carbon sources, under aerobic and anoxic conditions. These characteristics, together with its amenability to genetic manipulations, make P. denitrificans a promising cell factory for industrial biotechnology. This paper presents and validates the first functional genome-scale metabolic model for P. denitrificans, which is a key tool to enable P. denitrificans as a platform for metabolic engineering and industrial biotechnology. Optimization of the biomass yield led to accurate predictions in a broad scope of substrates.

Wastewater-based epidemiology for COVID-19 using dynamic artificial neural networks.

Global efforts in vaccination have led to a decrease in COVID-19 mortality but a high circulation of SARS-CoV-2 is still observed in several countries, resulting in some cases of severe lockdowns. In this sense, wastewater-based epidemiology remains a powerful tool for supporting regional health administrations in assessing risk levels and acting accordingly. In this work, a dynamic artificial neural network (DANN) has been developed for predicting the number of COVID-19 hospitalized patients in hospitals in Valladolid (Spain). This model takes as inputs a wastewater epidemiology indicator for COVID-19 (concentration of RNA from SARS-CoV-2 N1 gene reported from Valladolid Wastewater Treatment Plant), vaccination coverage, and past data of hospitalizations. The model considered both the instantaneous values of these variables and their historical evolution. Two study periods were selected (from May 2021 until September 2022 and from September 2022 to July 2023). During the first period, accurate predictions of hospitalizations (with an overall range between 6 and 171) were favored by the correlation of this indicator with N1 concentrations in wastewater (r = 0.43, p < 0.05), showing accurate forecasting for 1 day ahead and 5 days ahead. The second period's retraining strategy maintained the overall accuracy of the model despite lower hospitalizations. Furthermore, risk levels were assigned to each 1 day ahead prediction during the first and second periods, showing agreement with the level measured and reported by regional health authorities in 95 % and 93 % of cases, respectively. These results evidenced the potential of this novel DANN model for predicting COVID-19 hospitalizations based on SARS-CoV-2 wastewater concentrations at a regional scale. The model architecture herein developed can support regional health authorities in COVID-19 risk management based on wastewater-based epidemiology.

Assessment of the performance of a symbiotic microalgal-bacterial granular sludge reactor for the removal of nitrogen and organic carbon from dairy wastewater.

Cheese whey (CW) is a nutrient deficient dairy effluent, which requires external nutrient supplementation for aerobic treatment. CW, supplemented with ammonia, can be treated using aerobic granular sludge (AGS) in a sequencing batch reactor (SBR). AGS are aggregates of microbial origin that do not coagulate under reduced hydrodynamic shear and settle significantly faster than activated sludge flocs. However, granular instability, slow granulation start-up, high energy consumption and CO2 emission have been reported as the main limitations in bacterial AGS-SBR. Algal-bacterial granular systems have shown be an innovative alternative to improve these limitations. Unfortunately, algal-bacterial granular systems for the treatment of wastewaters with higher organic loads such as CW have been poorly studied. In this study, an algal-bacterial granular system implemented in a SBR (SBRAB) for the aerobic treatment of ammonia-supplemented CW wastewaters was investigated and compared with a bacterial granular reactor (SBRB). Mass balances were used to estimate carbon and nitrogen (N) assimilation, nitrification and denitrification in both set-ups. SBRB exhibited COD and ammonia removal of 100% and 94% respectively, high nitrification (89%) and simultaneous nitrification-denitrification (SND) of 23% leading to an inorganic N removal of 30%. The efficient algal-bacterial symbiosis in granular systems completely removed COD and ammonia (100%) present in the dairy wastewater. SBRAB microalgae growth could reduce about 20% of the CO2 emissions produced by bacterial oxidation of organic compounds according to estimates based on synthesis reactions of bacterial and algal biomass, in which the amount of assimilated N determined by mass balance was taken into account. A lower nitrification (75%) and minor loss of N by denitrifying activity (<5% Ng, SND 2%) was also encountered in SBRAB as a result of its higher biomass production, which could be used for the generation of value-added products such as biofertilizers and biostimulants.

Resilience and robustness of alphaproteobacterial methanotrophs upon methane feast-famine scenarios.

Most of methane (CH4) emissions contain low CH4 concentrations and typically occur at irregular intervals, which hinders the implementation and performance of methane abatement processes. This study aimed at understanding the metabolic mechanisms that allow methane oxidizing bacteria (MOB) to survive for long periods of time under methane starvation. To this aim, we used an omics-approach and studied the diversity and metabolism of MOB and non-MOB in bioreactors exposed to low CH4 concentrations under feast-famine cycles of 5 days and supplied with nutrient-rich broth. The 16S rRNA and the pmoA transcripts revealed that the most abundant and active MOB during feast and famine conditions belonged to the alphaproteobacterial genus Methylocystis (91-65%). The closest Methylocystis species were M. parvus and M. echinoides. Nitrifiers and denitrifiers were the most representative non-MOB communities, which likely acted as detoxifiers of the system. During starvation periods, the induced activity of CH4 oxidation was not lost, with the particulate methane monooxygenase of alphaproteobacterial MOB playing a key role in energy production. The polyhydroxyalkanoate and nitrification metabolisms of MOB had also an important role during feast-famine cycles, maintaining cell viability when CH4 concentrations were negligible. This research shows that there is an emergence and resilience of conventional alphaproteobacterial MOB, being the genus Methylocystis a centrepiece in environments exposed to dilute and intermittent methane emissions. This knowledge can be applied to the operation of bioreactors subjected to the treatment of dilute and discontinuous emissions via controlled bioaugmentation.

Botanical filters for the abatement of indoor air pollutants.

Nowadays, people spend 80-90% of their time indoors, while recent policies on energy efficient and safe buildings require reduced building ventilation rates and locked windows. These facts have raised a growing concern on indoor air quality, which is currently receiving even more attention than outdoors pollution. Prevention is the first and most cost-effective strategy to improve indoor air quality, but once pollution is generated, a battery of physicochemical technologies is typically implemented to improve air quality with a questionable efficiency and at high operating costs. Biotechnologies have emerged as promising alternatives to abate indoor air pollutants, but current bioreactor configurations and the low concentrations of indoor air pollutants limit their widespread implementation in homes, offices and public buildings. In this context, recent investigations have shown that potted plants can aid in the removal of a wide range of indoor air pollutants, especially volatile organic compounds (VOCs), and can be engineered in aesthetically attractive configurations. The original investigations conducted by NASA, along with recent advances in technology and design, have resulted in a new generation of botanical biofilters with the potential to effectively mitigate indoor air pollution, with increasing public aesthetics acceptance. This article presents a review of the research on active botanical filters as sustainable alternatives to purify indoor air.

Ectoines production from biogas in pilot bubble column bioreactors and their subsequent extraction via bio-milking.

Despite the potential of biogas from waste/wastewater treatment as a renewable energy source, the presence of pollutants and the rapid decrease in the levelized cost of solar and wind power constrain the use of biogas for energy generation. Biogas conversion into ectoine, one of the most valuable bioproducts (1000 €/kg), constitutes a new strategy to promote a competitive biogas market. The potential for a stand-alone 20 L bubble column bioreactor operating at 6% NaCl and two 10 L interconnected bioreactors (at 0 and 6% NaCl, respectively) for ectoine production from biogas was comparatively assessed. The stand-alone reactor supported the best process performance due to its highest robustness and efficiency for ectoine accumulation (20-52 mgectoine/gVSS) and CH4 degradation (up to 84%). The increase in N availability and internal gas recirculation did not enhance ectoine synthesis. However, a 2-fold increase in the internal gas recirculation resulted in an approximately 1.3-fold increase in CH4 removal efficiency. Finally, the recovery of ectoine through bacterial bio-milking resulted in efficiencies of >70% without any negative impact of methanotrophic cell recycling to the bioreactors on CH4 biodegradation or ectoine synthesis.

The co-conversion of methane and mixtures of volatile fatty acids into poly(3-hydroxybutyrate-co-3-hydroxyvalerate) expands the potential of an integrated biorefinery.

In this work, the potential of Methylocystis hirsuta to simultaneously use methane and volatile fatty acids mixtures for triggering PHBV accumulation was assessed for the first time batchwise. Biotic controls carried out with CH4 alone confirmed the inability of Methylocystis hirsuta to produce PHBV and achieved 71.2 ± 7 g m-3d-1 of PHB. Pure valeric acid and two synthetic mixtures simulating VFAs effluents from the anaerobic digestion of food waste at 35 °C (M1) and 55 °C (M2) were supplied to promote 3-HV inclusion. Results showed that pure valeric acid supported the highest polymer yields of 105.8 ± 9 g m-3d-1 (3-HB:3-HV=70:30). M1 mixtures led to a maximum of 103 ± 4 g m-3d-1 of PHBV (3-HB:3-HV=85:15), while M2 mixtures, which did not include valeric acid, showed no PHV synthesis. This suggested that the synthesis of PHBV from VFAs effluents depends on the composition of the mixtures, which can be tuned during the anaerobic digestion process.

Continuous polyhydroxybutyrate production from biogas in an innovative two-stage bioreactor configuration.

Biogas biorefineries have opened up new horizons beyond heat and electricity production in the anaerobic digestion sector. Added-value products such as polyhydroxyalkanoates (PHAs), which are environmentally benign and potential candidates to replace conventional plastics, can be generated from biogas. This work investigated the potential of an innovative two-stage growth-accumulation system for the continuous production of biogas-based polyhydroxybutyrate (PHB) using Methylocystis hirsuta CSC1 as cell factory. The system comprised two turbulent bioreactors in series to enhance methane and oxygen mass transfer: a continuous stirred tank reactor (CSTR) and a bubble column bioreactor (BCB) with internal gas recirculation. The CSTR was devoted to methanotrophic growth under nitrogen balanced growth conditions and the BCB targeted PHB production under nitrogen limiting conditions. Two different operational approaches under different nitrogen loading rates and dilution rates were investigated. A balanced nitrogen loading rate along with a dilution rate (D) of 0.3 day-1 resulted in the most stable operating conditions and a PHB productivity of ~53 g PHB m-3 day-1 . However, higher PHB productivities (~127 g PHB m-3 day-1 ) were achieved using nitrogen excess at a D = 0.2 day-1 . Overall, the high PHB contents (up to 48% w/w) obtained in the CSTR under theoretically nutrient balanced conditions and the poor process stability challenged the hypothetical advantages conferred by multistage vs single-stage process configurations for long-term PHB production.

Biological desulfurization of biogas: A comprehensive review on sulfide microbial metabolism and treatment biotechnologies.

Hydrogen sulphide (H2S) removal from biogas is of high relevance as it damages combustion engines used for heat and power generation and causes adverse public health and environmental effects. Biological processes have been reported as a cost-effective and promising approach to desulfurize biogas. This review presents a detailed description of the biochemical foundations of the metabolic apparatus of H2S oxidizing bacteria, namely chemolithoautotrophs and anoxygenic photoautotrophs. The review focuses on the current and future applications of biological processes for biogas desulfurization and provides insights into their mechanism and main factors influencing their performance. The advantages, drawbacks, limitations, and technical improvements of the biotechnological applications currently based on chemolithoautotrophic organisms are covered extensively. Recent advances, sustainability and economical aspects of biological biogas desulfurization are also discussed. Anoxygenic photoautotrophic-bacteria-based photobioreactors were herein identified as useful tools to improve the sustainability and safety of biological biogas desulfurization. The review addresses gaps in the existing studies concerning the selection of the most suitable desulfurization techniques, their benefits and consequences. The research is useful for all stakeholders involved in the management and optimization of biogas and its findings are directly applicable in the development of new sustainable technologies for biogas upgrading processes on waste treatment plants.

Continuous lactate-driven dark fermentation of restaurant food waste: Process characterization and new insights on transient feast/famine perturbations.

The effect of hydraulic retention time (HRT) on the continuous lactate-driven dark fermentation (LD-DF) of food waste (FW) was investigated. The robustness of the bioprocess against feast/famine perturbations was also explored. The stepwise HRT decrease from 24 to 16 and 12 h in a continuously stirred tank fermenter fed with simulated restaurant FW impacted on hydrogen production rate (HPR). The optimal HRT of 16 h supported a HPR of 4.2 L H2/L-d. Feast/famine perturbations caused by 12-h feeding interruptions led to a remarkable peak in HPR up to 19.2 L H2/L-d, albeit the process became stable at 4.3 L H2/L-d following perturbation. The occurrence of LD-DF throughout the operation was endorsed by metabolites analysis. Particularly, hydrogen production correlated positively with lactate consumption and butyrate production. Overall, the FW LD-DF process was highly sensitive but resilient against transient feast/famine perturbations, supporting high-rate HPRs under optimal HRTs.