Investigating the safety profiles of exogenous melatonin and associated adverse events: A pharmacovigilance study using WHO-VigiBase.

Melatonin, a pineal hormone that modulates circadian rhythms, sleep, and neurotransmitters, is widely used to treat sleep disorders. However, there are limited studies on the safety of melatonin. Therefore, we aimed to present the overall patterns of adverse events (AEs) following melatonin administration and identify potential safety signals associated with melatonin. Using VigiBase, a global individual case safety report (ICSRs) database managed by the World Health Organization (WHO), we conducted a retrospective, observational, pharmacovigilance study of melatonin between January 1996 and September 2022. Disproportionality analysis was conducted using two comparator settings: all other drugs and other sleep medications. We used multivariable logistic regression to estimate reporting odds ratios (RORs) with 95% confidence intervals (CIs) to compare the frequencies of AEs reporting between melatonin and each comparator setting. Furthermore, we assessed adverse events of special interests (AESIs) that could potentially be associated with melatonin. Signals were identified when the following criteria were met: cases ≥3, x2 ≥ 4, IC025 ≥ 0, and the lower end of the 95% CI of ROR > 2. These signals were then compared with the AE information on the drug labels provided by regulatory bodies. A total of 35 479 AE reports associated with melatonin were identified, with a higher proportion of reports from females (57.1%) and individuals aged 45-64 years (20.8%). We identified 21 AEs that were commonly detected as safety signals in the disproportionality analyses, including tic, educational problems, disturbance in social behavior, body temperature fluctuation, and growth retardation. In AESI analyses, accidents and injuries (adjusted ROR 2.97; 95% CI, 2.80-3.16), fall (2.24; 2.12-2.37), nightmare (4.90; 4.37-5.49), and abnormal dreams (3.68; 3.19-4.25) were detected as a signal of melatonin when compared to all other drugs, whereas those signals were not detected when compared to other sleep medications. In this pharmacovigilance study, exogenous melatonin showed safety profiles comparable to other sleep medications. However, several unexpected potential safety signals were identified, underscoring the need for further investigation at the population level.

Bi-Allelic UQCRFS1 Variants Are Associated with Mitochondrial Complex III Deficiency, Cardiomyopathy, and Alopecia Totalis.

Isolated complex III (CIII) deficiencies are among the least frequently diagnosed mitochondrial disorders. Clinical symptoms range from isolated myopathy to severe multi-systemic disorders with early death and disability. To date, we know of pathogenic variants in genes encoding five out of 10 subunits and five out of 13 assembly factors of CIII. Here we describe rare bi-allelic variants in the gene of a catalytic subunit of CIII, UQCRFS1, which encodes the Rieske iron-sulfur protein, in two unrelated individuals. Affected children presented with low CIII activity in fibroblasts, lactic acidosis, fetal bradycardia, hypertrophic cardiomyopathy, and alopecia totalis. Studies in proband-derived fibroblasts showed a deleterious effect of the variants on UQCRFS1 protein abundance, mitochondrial import, CIII assembly, and cellular respiration. Complementation studies via lentiviral transduction and overexpression of wild-type UQCRFS1 restored mitochondrial function and rescued the cellular phenotype, confirming UQCRFS1 variants as causative for CIII deficiency. We demonstrate that mutations in UQCRFS1 can cause mitochondrial disease, and our results thereby expand the clinical and mutational spectrum of CIII deficiencies.

A cleavage-based surrogate reporter for the evaluation of CRISPR-Cas9 cleavage efficiency.

CRISPR-Cas9 is a powerful tool for genome engineering, but its efficiency largely depends on guide RNA (gRNA). There are multiple methods available to evaluate the efficiency of gRNAs, including the T7E1 assay, surveyor nuclease assay, deep sequencing, and surrogate reporter systems. In the present study, we developed a cleavage-based surrogate that we have named the LacI-reporter to evaluate gRNA cleavage efficiency. The LacI repressor, under the control of the EF-1α promoter, represses luciferase or EGFP reporter expression by binding to the lac operator. Upon CRISPR-Cas9 cleavage at a target site located between the EF-1α promoter and the lacI gene, repressor expression is disrupted, thereby triggering luciferase or EGFP expression. Using this system, we can quantitate gRNA cleavage efficiency by assessing luciferase activity or EGFP expression. We found a strong positive correlation between the cleavage efficiency of gRNAs measured using this reporter and mutation frequency, measured using surveyor and deep sequencing. The genome-editing efficiency of gRNAs was validated in human liver organoids. Our LacI-reporter system provides a useful tool to select efficient gRNAs for genome editing.

SARS-CoV-2 B.1.619 and B.1.620 Lineages, South Korea, 2021.

We report the rapid emergence of severe acute respiratory syndrome coronavirus 2 lineages B.1.619 and B.1.620 in South Korea. The surge in frequency in a relatively short time emphasizes the need for ongoing monitoring for new lineages to track potential increases in transmissibility and disease severity and reductions in vaccine efficacy.

Genomic evidence of SARS-CoV-2 reinfection in the Republic of Korea.

As the coronavirus disease 2019 (COVID-19) pandemic continues, reinfection is likely to become increasingly common. However, confirming COVID-19 reinfection is difficult because it requires whole-genome sequencing of both infections to identify the degrees of genetic differences. Since the first reported case of reinfection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the Republic of Korea in April 2020, four additional cases were classified as suspected reinfection cases. We performed whole-genome sequencing of viral RNA extracted from swabs obtained at the initial infection and reinfection stages of these four suspected cases. The interval between initial infection and reinfection of all four suspected cases was more than 3 months. All four patients were young (10-29 years), and they displayed mild symptoms or were asymptomatic during the initial infection and reinfection episodes. The analysis of genome sequences combined with the epidemiological results revealed that only two of the four cases were confirmed as reinfection, and both were reinfected with the Epsilon variant. Due to the prolonged COVID-19 pandemic, the possibility of reinfections with SARS-CoV-2 variants is increasing, as reported in our study. Therefore, continuous monitoring of cases is necessary.

G9a Knockdown Suppresses Cancer Aggressiveness by Facilitating Smad Protein Phosphorylation through Increasing BMP5 Expression in Luminal A Type Breast Cancer.

Epigenetic abnormalities affect tumor progression, as well as gene expression and function. Among the diverse epigenetic modulators, the histone methyltransferase G9a has been focused on due to its role in accelerating tumorigenesis and metastasis. Although epigenetic dysregulation is closely related to tumor progression, reports regarding the relationship between G9a and its possible downstream factors regulating breast tumor growth are scarce. Therefore, we aimed to verify the role of G9a and its presumable downstream regulators during malignant progression of breast cancer. G9a-depleted MCF7 and T47D breast cancer cells exhibited suppressed motility, including migration and invasion, and an improved response to ionizing radiation. To identify the possible key factors underlying these effects, microarray analysis was performed, and a TGF-ß superfamily member, BMP5, was selected as a prominent target gene. It was found that BMP5 expression was markedly increased by G9a knockdown. Moreover, reduction in the migration/invasion ability of MCF7 and T47D breast cancer cells was induced by BMP5. Interestingly, a G9a-depletion-mediated increase in BMP5 expression induced the phosphorylation of Smad proteins, which are the intracellular signaling mediators of BMP5. Accordingly, we concluded that the observed antitumor effects may be based on the G9a-depletion-mediated increase in BMP5 expression and the consequent facilitation of Smad protein phosphorylation.

Glucosylceramide synthase regulates adipo-osteogenic differentiation through synergistic activation of PPARγ with GlcCer.

Dysregulation of the adipo-osteogenic differentiation balance of mesenchymal stem cells (MSCs), which are common progenitor cells of adipocytes and osteoblasts, has been associated with many pathophysiologic diseases, such as obesity, osteopenia, and osteoporosis. Growing evidence suggests that lipid metabolism is crucial for maintaining stem cell homeostasis and cell differentiation; however, the detailed underlying mechanisms are largely unknown. Here, we demonstrate that glucosylceramide (GlcCer) and its synthase, glucosylceramide synthase (GCS), are key determinants of MSC differentiation into adipocytes or osteoblasts. GCS expression was increased during adipogenesis and decreased during osteogenesis. Targeting GCS using RNA interference or a chemical inhibitor enhanced osteogenesis and inhibited adipogenesis by controlling the transcriptional activity of peroxisome proliferator-activated receptor γ (PPARγ). Treatment with GlcCer sufficiently rescued adipogenesis and inhibited osteogenesis in GCS knockdown MSCs. Mechanistically, GlcCer interacted directly with PPARγ through A/B domain and synergistically enhanced rosiglitazone-induced PPARγ activation without changing PPARγ expression, thereby treatment with exogenous GlcCer increased adipogenesis and inhibited osteogenesis. Animal studies demonstrated that inhibiting GCS reduced adipocyte formation in white adipose tissues under normal chow diet and high-fat diet feeding and accelerated bone repair in a calvarial defect model. Taken together, our findings identify a novel lipid metabolic regulator for the control of MSC differentiation and may have important therapeutic implications.

Anti-Inflammatory Activities of the Ethanol Extract of Prasiola japonica, an Edible Freshwater Green Algae, and Its Various Solvent Fractions in LPS-Induced Macrophages and Carrageenan-Induced Paw Edema via the AP-1 Pathway.

Prasiola japonica possesses several biological activities. However, reports on the anti-inflammatory activities and molecular mechanisms of its different solvent fractions remain limited. In this study, we investigated the potential anti-inflammatory activities of P. japonica ethanol extract (Pj-EE) and four solvent fractions of Pj-EE made with hexane (Pj-EE-HF), chloroform (Pj-EE-CF), butanol (Pj-EE-BF), or water (Pj-EE-WF) in both in vitro (LPS-induced macrophage-like RAW264.7 cells) and in vivo (carrageenan-induced acute paw edema mouse models) experiments. The most active solvent fraction was selected for further analysis. Various in vitro and in vivo assessments, including nitric oxide (NO), cytokines, luciferase assays, real-time polymerase chain reactions, and immunoblotting analyses were performed to evaluate the underlying mechanisms. In addition, the phytochemical constituents were characterized by Liquid chromatography-tandem mass spectrometry. In in vitro studies, the highest inhibition of NO production was observed in Pj-EE-CF. Further examination revealed that Pj-EE-CF decreased the expression of inflammation-related cytokines in LPS-induced RAW264.7 cells and suppressed subsequent AP-1-luciferase activity by inhibition of phosphorylation events in the AP-1 signaling pathway. Pj-EE-CF treatment also demonstrated the strongest reduction in thickness and volume of carrageenan-induced paw edema, while Pj-EE-BF showed the lowest activity. Furthermore, Pj-EE-CF also reduced gene expression and cytokines production in tissue lysates of carrageenan-induced paw edema. These findings support and validate the evidence that Pj-EE, and especially Pj-EE-CF, could be a good natural source for an anti-inflammatory agent that targets the AP1 pathway.

Electroactive microorganisms enriched from activated sludge remove nitrogen in bioelectrochemical reactor.

The bioelectrochemical anaerobic nitrogen removal was demonstrated in an anaerobic batch reactor equipped with a pair of polarized bioelectrodes. The bioelectrochemical reactor was operated in sequential batch mode after inoculating activated sludge and polarizing the electrode to 0.6 V. The medium contains ammonium, nitrite, alkalinity and trace minerals, but no organic carbon source. By the repetitive sequential operation, simultaneous removals of ammonium, nitrite and alkalinity were improved, and the electrochemical activity of the bulk sludge was confirmed from the redox peaks of the cyclic voltammogram. This indicates that ammonia oxidizing exoelectrogens (AOE) and denitritating electrotrophs (DNE) were enriched more in the bulk solution. Biogas production that mainly consisted of nitrogen was observed from the bioelectrochemical reactor, and the minor components in the biogas were methane and carbon dioxide. This demonstrates that AOE use nitrite as an electron acceptor to oxidize ammonia. The requirements of nitrite and alkalinity for the removal of ammonia nitrogen are around 0.72 mg NO2-N/mg NH4-N and 1.73 mg as CaCO3/mg NH4-N, respectively, and nitrate was not produced as a by-product. The bacterial groups involved in the bioelectrochemical nitrogen removal are electroactive autotrophs and can be enriched from activated sludge by polarized electrode. This bioelectrochemical ammonia oxidation is a novel approach recommended for treatment of nitrogen-rich wastewater.

Uric acid level may not be reduced in essential tremor.

BACKGROUND: Essential tremor is very common, but characterization is difficult because of its heterogeneity. Neuropathology is important to elucidate the characteristics of neurological disorders. However, pathological findings in essential tremor have been inconsistent among studies. Uric acid is a strong antioxidant and might be a biomarker in neurodegenerative process. We hypothesized that uric acid level would be reduced if essential tremor is a neurodegenerative disease. Our aim was to compare uric acid level between essential tremor patients and healthy individuals. METHODS: This was a prospective, case-control, multicenter study with 92 essential tremor patients and 77 healthy subjects. For homogeneity, the essential tremor group was subdivided into two groups (hereditary and sporadic). Clinical and laboratory findings were compared among the essential tremor and healthy groups. RESULTS: The demographic characteristics were comparable among the groups. The uric acid level was lower in the essential tremor group than in healthy subjects, but the difference did not reach statistical significance. There was a negative correlation between uric acid level and disease duration in the hereditary group (p = .046) and between uric acid level and age at onset in the sporadic group (p = .012). The mean values of total cholesterol were significantly lower in the sporadic group than in the other groups (p = .011). Total cholesterol was positively correlated with age at onset in the hereditary essential tremor group (p = .010). CONCLUSIONS: We did not find any evidence that uric acid levels suggested essential tremor is a neurodegenerative disease. However, further research with more patients might be needed given the negative correlations of disease duration and age at onset with uric acid level.

Neutralization Testing-based Immunogenicity Analysis of Recent Prevalent Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Sublineages.

Although WHO declared the end of the public health emergency for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), XBB lineages continue to evolve and emerge globally. In particular, XBB.1.5 and XBB.1.16 are raising concerns because of their high immune evasion, leading to apprehensions regarding vaccine efficacy reduction and potential reinfection. We aimed to investigate the COVID-19 outbreak in Korea and predict the likelihood of reinfection by testing neutralizing activity against live viruses from the S clade and 19 Omicron sublineages. We found a significant risk of infection with the currently prevalent XBB lineage for individuals who were either vaccinated early or infected during the initial Omicron outbreak. Vaccinated individuals were better equipped than unvaccinated individuals to produce neutralizing antibodies for other SARS-CoV-2 variants upon infection. Therefore, unvaccinated individuals do not easily develop neutralizing activity against other variants and face the highest risk of reinfection by the XBB lineage. Our study provides important information to facilitate the development of strategies for monitoring populations that would be the most susceptible to new COVID-19 outbreaks.

Three distinct ORF1a recombinants of the SARS-CoV-2 Delta variant of concern.

The ongoing COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the emergency of various lineages through mutations and recombination. In the Delta lineage, we identified recombination events in the ORF1a gene, which divided the Delta sublineages into three different genotypes (Delta R1-R3). The regional distributions of Delta R1 and Delta R2 were not correlated, indicating that recombination occurred early in the Delta outbreak. The impact of the ORF1a gene on SARS-CoV-2 transmission remains unclear; however, our findings suggest that recombination may have contributed to the evolution and global spread of the Delta lineage.

The unique liquid-based cytologic findings of thyroid signet-ring follicular adenoma: a report of two cases with fine needle aspiration cytology.

BACKGROUND: Signet-ring follicular adenoma is a rare variant of follicular neoplasm, which has only been described using the conventional smear cytologic preparation. Here we report the unique cytologic findings of two cases of signet-ring follicular adenoma using liquid-based samples and corresponding histologic features and results of ancillary tests. CASES: Case 1: A 65-year-old man presented with a solitary nodule in the right lobe of the thyroid. Ultrasound-guided fine needle aspiration (FNA) yielded several groups of microfollicles containing colloid or mucin-like globules. The tumor cells had eccentrically located nuclei compressed by distended luminal globules. Case 2: A 51-year-old woman presented with a nodule in the left lobe of the thyroid. On liquid-based cytology, cord-like arrangements of microfollicules were noted. The tumor cells had large, clear vacuoles, but the nuclei maintained their round shape and central location. CONCLUSION: The liquid-based cytologic characteristics are quite different from those encountered in the conventional smear of FNA; therefore, pathologists must also be familiar with the cytomorphologic characteristics of liquid-based preparations. In addition, given the distinctive cytological and histological appearance and the benign clinical course, signet-ring follicular adenoma should be distinguished from other metastatic neoplasms displaying signet-ring cell features.

Genomic epidemiology of SARS-CoV-2 variants in South Korea between January 2020 and February 2023.

The Korea Disease Control and Prevention Agency (KDCA) has been conducting national genomic surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). To monitor and characterize circulating SARS-CoV-2 variants in South Korea, 102,873 oropharyngeal/nasopharyngeal swab samples collected from patients with confirmed COVID-19 were sequenced, assigned lineages, and phylogenetically analyzed. Each wave followed a pattern of variants emerging first abroad and then spreading domestically. In 2020, B.41 lineage led the first wave, and B.1.497 dominated the second and third waves. In 2021, the fourth wave was driven by Delta (AY.69 and AY.122.5). In 2022, the fifth to seventh waves were dominated by Omicron sub-lineages BA.1/BA.1.1 and BA.2/BA.2.3, BA.5/BA.5.2, and BN.1, sequentially. The KDCA detected and monitored increasing variants in advance prior to large-scale epidemics, but the repeated emergence of new variants could threaten public health again. Therefore, it is important to continue to monitor and characterize emerging and circulating variants through national genomic surveillance.

Downregulation of complement factor H attenuates the stemness of MDA­MB­231 breast cancer cells via modulation of the ERK and p38 signaling pathways.

The complement system is a powerful innate immune system deployed in the immediate response to pathogens and cancer cells. Complement factor H (CFH), one of the regulators involved in the complement cascade, can interrupt the death of target cells. Certain types of cancer, such as breast cancer, can adopt an aggressive phenotype, such as breast cancer stem cells (BCSCs), through enhancement of the defense system against complement attack by amplifying various complement regulators. However, little is known about the association between CFH and BCSCs. In the present study, the roles of CFH in the CSC characteristics and radioresistance of MDA-MB-231 human breast cancer cells were investigated. CFH knockdown in MDA-MB-231 cells decreased the viability of the cells upon complement cascade activation. Notably, CFH knockdown also decreased cell survival and suppressed mammosphere formation, cell migration and cell invasion by attenuating radioresistance. Additionally, CFH knockdown further enhanced irradiation-induced apoptosis through G2/M cell cycle arrest. It was also discovered that CFH knockdown attenuated the aggressive phenotypes of cancer cells by regulating CSC-associated gene expression. Finally, by microarray analysis, it was found that the expression of erythrocyte membrane protein band 4.1-like 3 (EPB41L3) was markedly increased following CFH knockdown. EPB41L3 inhibited ERK and activated the p38 MAPK signaling pathway. Taken together, these results indicated that CFH knockdown attenuated CSC properties and radioresistance in human breast cancer cells via controlling MAPK signaling and through upregulation of the tumor suppressor, EPB41L3.

Increased viral load in patients infected with severe acute respiratory syndrome coronavirus 2 Omicron variant in the Republic of Korea.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has been declared a global pandemic owing to the rapid spread of the causative agent, severe acute respiratory syndrome coronavirus 2. Its Delta and Omicron variants are more transmissible and pathogenic than other variants. Some debates have emerged on the mechanism of variants of concern. In the COVID-19 wave that began in December 2021, the Omicron variant, first reported in South Africa, became identifiable in most cases globally. The aim of this study was to provide data to inform effective responses to the transmission of the Omicron variant. METHODS: The Delta variant and the spike protein D614G mutant were compared with the Omicron variant. Viral loads from 5 days after symptom onset were compared using epidemiological data collected at the time of diagnosis. RESULTS: The Omicron variant exhibited a higher viral load than other variants, resulting in greater transmissibility within 5 days of symptom onset. CONCLUSION: Future research should focus on vaccine efficacy against the Omicron variant and compare trends in disease severity associated with its high viral load.

GPR143 controls ESCRT-dependent exosome biogenesis and promotes cancer metastasis.

Exosomes transport a variety of macromolecules and modulate intercellular communication in physiology and disease. However, the regulation mechanisms that determine exosome contents during exosome biogenesis remain poorly understood. Here, we find that GPR143, an atypical GPCR, controls the endosomal sorting complex required for the transport (ESCRT)-dependent exosome biogenesis pathway. GPR143 interacts with HRS (an ESCRT-0 Subunit) and promotes its association to cargo proteins, such as EGFR, which subsequently enables selective protein sorting into intraluminal vesicles (ILVs) in multivesicular bodies (MVBs). GPR143 is elevated in multiple cancers, and quantitative proteomic and RNA profiling of exosomes in human cancer cell lines showed that the GPR143-ESCRT pathway promotes secretion of exosomes that carry unique cargo, including integrins signaling proteins. Through gain- and loss-of-function studies in mice, we show that GPR143 promotes metastasis by secreting exosomes and increasing cancer cell motility/invasion through the integrin/FAK/Src pathway. These findings provide a mechanism for regulating the exosomal proteome and demonstrate its ability to promote cancer cell motility.

Evaluation of Radiation Sensitivity Differences in Mouse Liver Tumor Organoids Using CRISPR/Cas9-Mediated Gene Mutation.

BACKGROUND: To assess the radiosensitivity of liver tumors harboring different genetic mutations, mouse liver tumors were generated in vivo through the hydrodynamic injection of clustered regularly interspaced short palindromic repeat/caspase 9 (CRISPR/Cas9) constructs encoding single-guide RNAs (sgRNAs) targeting Tp53, Pten, Nf1, Nf2, Tsc2, Cdkn2a, or Rb1. METHODS: The plasmid vectors were delivered to the liver of adult C57BL/6 mice via hydrodynamic tail vein injection. The vectors were injected into 10 mice in each group. Organoids were generated from mouse liver tumors. The radiation response of the organoids was assessed using an ATP cell viability assay. RESULTS: The mean survival period of mice injected with vectors targeting Nf2 (4.8 months) was lower than that of other mice. Hematoxylin and eosin staining, immunohistochemical (IHC) staining, and target sequencing analyses revealed that mouse liver tumors harbored the expected mutations. Tumor organoids were established from mouse liver tumors. Histological evaluation revealed marked morphological similarities between the mouse liver tumors and the generated tumor organoids. Moreover, IHC staining indicated that the parental tumor protein expression pattern was maintained in the organoids. The results of the ATP cell viability assay revealed that the tumor organoids with mutated Nf2 were more resistant to high-dose radiation than those with other gene mutations. CONCLUSIONS: This study developed a radiation response assessment system for mouse tumors with mutant target genes using CRISPR/Cas9 and organoids. The Tp53 and Pten double mutation in combination with the Nf2 mutation increased the radiation resistance of tumors. The system used in this study can aid in elucidating the mechanism underlying differential intrinsic radiation sensitivity of individual tumors.

A Seroprevalence Study on Residents in a Senior Care Facility with Breakthrough SARS-CoV-2 Omicron Infection.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began spreading rapidly in the community in November 2021, becoming the dominant variant in the Republic of Korea in 2022. Although its pathogenesis in healthy individuals was low, the severity and hospitalization rate was higher in the elderly and immunocompromised patients. We aimed to investigate the immunogenicity in acute and convalescent phases of breakthrough infection by Omicron in elderly individuals. Serological data were assessed by electrochemiluminescence immunoassay, enzyme-linked immunosorbent assay, and plaque-reduction neutralization tests. SARS-CoV-2-specific antibody and immunoglobulin G levels in the acute phase were higher in third dose-vaccinated elderly than in first and second dose-vaccinated patients. The neutralization antibody titer was detected only in third dose-vaccinated patients, and the titer was higher for the Delta than the Omicron variant. In the convalescent phase of Omicron infection, the neutralization antibody titer of vaccinated patients was higher for the Delta than the Omicron variant except in unvaccinated individuals. We demonstrated that the cause of the vulnerability to Omicron variant infection in third dose-vaccinated elderly was due to the low neutralization antibody level against Omicron. A fourth dose of vaccination is required in the elderly to reduce hospitalization and mortality caused by the Omicron variant.

Exploration of deep learning models for real-time monitoring of state and performance of anaerobic digestion with online sensors.

The immediate response to the state disturbances of anaerobic digestion is essential to prevent anaerobic digestion failure. However, frequent monitoring of the state and performance of anaerobic digestion is challenging. Thus, deep learning models were investigated to predict the state and performance variables from online sensor data. The online sensor data, including pH, electric conductivity, and oxidation-reduction potential, were used as the input features to build deep learning models. The state and performance data measured offline were used as the labels. The model performance was compared for several deep learning models of convolutional neural network (CNN), long short-term memory (LSTM), dense layer, and their combinations. The combined model of CNN and bidirectional LSTM was robust and well-generalized in predicting the state and performance variables (R2 = 0.978, root mean square error = 0.031). The combined model is an excellent soft sensor for monitoring the state and performance of anaerobic digestion from electrochemical sensors.