Body fluids should be identified before estimating the time since deposition (TsD) in microbiome-based stain analyses for forensics

Identification and the time since deposition (TsD) estimation of body fluid stains from a crime scene could provide valuable information for solving the cases and are always difficult for forensics. Microbial characteristics were considered as a promising biomarker to address the issues. However, changes in the microbiota may damage the specific characteristics of body fluids. Correspondingly, incorrect body fluid identification may result in inaccurate TsD estimation. The mutual influence is not well understood and limited the codetection. In the current study, saliva, semen, vaginal secretion, and menstrual blood samples were exposed to indoor conditions and collected at eight time points (from fresh to 30 days). High-throughput sequencing based on the 16S rRNA gene was performed to characterize the microbial communities. The results showed that a longer TsD could decrease the discrimination of different body fluid stains. However, the accuracies of identification still reached a quite high value even without knowing the TsD. Correspondingly, the mean absolute error (MAE) of TsD estimation significantly increased without distinguishing the types of body fluids. The predictive TsD of menstrual blood reached a quite low MAE (1.54 ± 0.39 d). In comparison, those of saliva (6.57 ± 1.17 d), semen (6.48 ± 1.33 d), and vaginal secretion (5.35 ± 1.11 d) needed to be further improved. The great effect of individual differences on these stains limited the TsD estimation accuracy. Overall, microbial characteristics allow for codetection of body fluid identification and TsD estimation, and body fluids should be identified before estimating TsD in microbiome-based stain analyses.IMPORTANCEEmerged evidences suggest microbial characteristics could be considered a promising tool for identification and time since deposition (TsD) estimation of body fluid stains. However, the two issues should be studied together due to a potential mutual influence. The current study provides the first evidence to understand the mutual influence and determines an optimal process for codetection of identification and TsD estimation for unknown stains for forensics. In addition, we involved aged stains into our study for identification of body fluid stains, rather than only using fresh stains like previous studies. This increased the predictive accuracy. We have preliminary verified that individual differences in microbiotas limited the predictive accuracy of TsD estimation for saliva, semen, and vaginal secretion. Microbial characteristics could provide an accurate TsD estimation for menstrual blood. Our study benefits the comprehensive understanding of microbiome-based stain analyses as an essential addition to previous studies.

Microbial and Physico-Chemical Characterization of Cold Smoked Sea Bass (Dicentrarchus labrax), a New Product of Fishery

The aim of this study was to investigate the microbial and physico-chemical characteristics of cold smoked sea bass (CSSB), a novel italian fish product. The microbiological analyses showed the presence of bacterial contamination from the raw material, the environment, and the production process. The microbial spoilage population was dominated by lactic acid bacteria (LAB) associated with Gram-negative fermenting bacteria, including Photobacterium phosphoreum and psychrotrophic Enterobacteriaceae. Brochotrix thermospacta and Aeromonas spp. were also present; in contrast, mould and yeast were not detected (<2 CFU/g). High levels (6-7 log CFU/g) of LAB and total bacteria count (TBC) were observed from day 45 of storage; however, their presence does not seem to have influenced the total volatile basic nitrogen (TVB-N), which always remained below 35 mg N/100 g. Consequently, the product is acceptable until day 60 of storage, considering that the malonaldehyde index (TBARS) was lower than 6.5 nmol/g. Pathogenic bacteria such as Salmonella spp. and Listeria monocytogenes were not detected. Currently, there is a growing demand for seafood due to its high quality and nutritional value. Cold smoked sea bass offers a source of macro- and micronutrients essential for the proper functioning of the human body. It is also rich in protein and omega-3 fatty acids. The WHO and FAO evaluated the benefits and risks and concluded that there is convincing evidence of health benefits from fish consumption, such as a reduction in the risk of heart failure and improved neurodevelopment in infants and young children when fish is consumed by the mother before and during pregnancy. The CSSB analysed in this study demonstrated to have health benefits due to long-chain omega-3 PUFAs and other nutrients, such as proteins, minerals, and vitamin D, which are sometimes difficult to obtain from other sources. The results show that CSSB has a high nutritional value and excellent microbial quality.

Study of enhanced nitrogen removal efficiency and microbial characteristics of an improved two-stage A/O process

During the cold winter in northern China, the temperature is generally below 8°C, and low water temperature significantly inhibits biological treatment processes, especially the biological denitrification process. To solve this problem, this study proposed an improved two-stage A/O process with built-in submerged biofilm modules. Experimental water was acquired from the Sanbaotun Wastewater Treatment Plant, which is situated in the city of Fushun, Liaoning Province. After one year of experimental research, the improved two-stage A/O process proved to be significantly better than the traditional two-stage A/O process, especially in winter. In the one-year experiment, the average removal rates of COD, TN, and NH₄⁺-N in the improved two-stage A/O process were 85.2%, 77.6%, and 96.9%, respectively. Microbial properties of the process were studied by means of high-throughput sequencing. High-throughput sequencing was conducted on the biofilm of the improved two-stage A/O terminal aerobic tank and the activated sludge of the conventional two-stage A/O aerobic tank. The result showed that the microbial diversity and abundance of the biofilms were considerably higher than those of the activated sludge during stable operation in winter. Under low-temperature conditions, the main denitrifying bacteria of the improved two-stage A/O process was Terrimonas, belonging to the sphingolipid class of Bacteroides, and the main genus of nitrifying bacteria was Nitrospira, belonging to the nitrite oxidizing bacteria.

Haloarchaea, excellent candidates for removing pollutants from hypersaline wastewater

Hypersaline wastewater is difficult to treat due to the inhibition of salt stress on microbes' viability and metabolic capabilities. Haloarchaea, native microorganisms that thrive in hypersaline habitats, overcome this key obstacle naturally. This review provides a comprehensive overview of the metabolic versatility of Haloarchaea in hypersaline wastewater treatment, including carbon, nitrogen, phosphorus, sulfur, and heavy metal metabolism. It also analyzes factors affecting pollutant removal and addresses metabolic mechanisms. Additionally, haloarchaea microbial characteristics and strategies to cope with salt stress are highlighted. Finally, the biotechnological potential of biomolecules produced from haloarchaea is investigated. To get better insight into the potential of haloarchaea, a deeper investigation of basic metabolism and more in-depth studies of their genomics and applications in actual wastewater are also necessary.

FeOx@GAC catalyzed microbubble ozonation coupled with biological process for industrial phenolic wastewater treatment: Catalytic performance, biological process screening and microbial characteristics

Phenolic compounds are common ccontaminants in industrial effluents. In this study, a combined catalytic microbubble ozonation and biological process was developed and applied for efficient industrial phenolic wastewater (PWW) treatment. Catalytic activity of an iron-oxides (FeO_x) doped granular activated carbon (GAC) catalyst (FeO_x@GAC) in microbubble ozonation for PWW treatment was investigated. The results demonstrated that the FeO_x@GAC catalyzed microbubble ozonation (O₃/FeO_x@GAC) obtained significantly higher reaction rate constant (k₁ = 0.023 min^-1) in TOC removal compared to the bare GAC catalyzed microbubble ozonation (O₃/GAC, k₁ = 0.013 min^-1) and ordinary microbubble ozonation (k₁ = 0.008 min^-1). Destruction rate constant of phenolic compounds (k₂) was improved from 0.014 min^-1 (ordinary microbubble ozonation) to 0.025 min^-1 (O₃/FeO_x@GAC). The 60-min pretreatment of PWW by O₃/FeO_x@GAC process enhanced BOD₅/COD ratio from 0.31 to 0.76 and reduced the acute bio-toxicity by 79.2%. Screening and characterization of biological post-treatment processes were conducted among activated sludge process (ASP), up-flow anaerobic sludge blanket (UASB) and membrane bioreactor (MBR). UASB and ASP showed limited phenolic compounds removal of 35.4% and 57.0% with lower bio-toxicity resistance than MBR (94.9% phenolic compounds removal). The combined process O₃/FeO_x@GAC-MBR was thus developed and achieved high COD removal (98.0%) and phenolic compounds degradation (99.4%). PWW pretreatment by O₃/FeO_x@GAC process decreased membrane fouling rate of MBR by 88.2% by reducing proteins/polysaccharides accumulation in both extracellular polymeric substances and soluble microbial products. 16S rRNA high-throughput sequencing revealed the predominance of phylum Proteobacteria, class Alphaproteobacteria and genera Mycobacterium, Gordonia, Pedomicrobium & Defluviimonas in biological PWW treatment bio-systems. Pearson correlation coefficient and ANOVA analysis verified that Mycobacterium possessed high bio-toxicity resistance and was the main contributor to the biodegradation of phenolic compounds.

[Effects of different coated slow-release calcium peroxide on microbial characteristics of gleyed paddy soil]

To explore the effects of different coated slow-release calcium peroxide on soil microbial characteristics in gleyed paddy field, we set seven treatments by simulation test in a greenhouse, including CK (none calcium peroxide), calcium peroxide powder, calcium peroxide particle and other four coated slow-release calcium peroxide treatments. Samples were collected in same tillering stage of early season rice. The results showed that all the applications of calcium peroxide could improve the concentrations of active soil organic carbon, soil available nutrients, soil microbial biomass, culturable microorganism population, as well as soil enzyme activity. The coated slow-release calcium peroxide had stronger effects than calcium peroxide particles and calcium peroxide powder. The calcium peroxide coated by ethyl cellulose was the most effective, which enhanced soil active organic carbon, soil microbial biomass carbon, nitrogen, phosphorus by 19.4%, 11.4%, 121.5% and 127.2%, soil alkaline hydrolysis nitrogen and available phosphorus by 4.0% and 45.5%, soil culturable bacteria and culturable microorganism population by 137.3% and 113.7%, fungi and actinomyces number were increased by 33.6% and 44.7%. The enzyme activities of invertase, phosphatase, urease as well as catalase were increased by 92.4%, 91.8%, 112.5% and 17.1%, respectively. The results could provide reference for improving gleyed paddy field with coated calcium peroxide.

Biogenic Amine Contents and Microbial Characteristics of Cambodian Fermented Foods

Naturally fermented foods are an important part of the typical diet in Cambodia. However, the food safety status of these products has not been widely studied. The aim of this study was, therefore, to provide an overview of the quality of these foods in relation to microbiology and biogenic amines. Additionally, the obtained results were compared to the habits and practices of Cambodians in handling this type of food. A total of 57 fermented foods (42 fishery and 15 vegetable products) were collected from different retail markets in the capital of Cambodia. Pathogenic Salmonella spp., Listeria spp., and Listeria monocytogenes were not detected in 25 g samples. Generally, less than 102 cfu/g of Staphylococcus aureus, Escherichia coli, Pseudomonas spp., Enterobacteriaceae, and molds were present in the fermented foods. Bacillus cereus group members (<102 to 2.3 × 104 cfu/g), lactic acid bacteria (<102 to 1.1 × 107 cfu/g), halophilic and halotolerant bacteria (<102 to 8.9 × 106 cfu/g), sulfite-reducing Clostridium spp. (<102 to 3.5 × 106 cfu/g), and yeasts (<102 to 1.1 × 106 cfu/g) were detected in this study. Still, the presence of pathogenic and spoilage microorganisms in these fermented foods was within the acceptable ranges. Putrescine, cadaverine, tyramine, and histamine were detected in 100%, 89%, 81%, and 75% of the tested products, respectively. The concentrations of histamine (>500 ppm) and tyramine (>600 ppm) were higher than the recommended maximum levels in respectively four and one of 57 fermented foods, which represents a potential health risk. The results suggest that the production process, distribution, and domestic handling of fermented foods should be re-evaluated. Further research is needed for the establishment of applicable preservation techniques in Cambodia.

[Microbial characteristics and eco-health implication of mineral spring water in Wudalianchi, Northeast China]

Mineral spring water is a top quality potable groundwater resource formed by long-term groundwater-rock interaction in aquifer. Mineral spring water is rich in minerals and trace elements which are beneficial for human health. Given the current serious water pollution and environment deterioration, it is of great significance to re-recognize the ecological and health effects of mineral water based on new scientific and technological achievement. The Wudalianchi scenic area in Heilongjiang Province has abundant mineral water and peloid resources, which supported the development of tourism and convalescence and have been used in medical and health care for more than 100 years. However, it is threatened by resource reduction, environmental pollution, and other problems. Here, we reviewed the formation process, distribution, hydro-biochemical characteristics and health effects of the Wudalianchi mineral springs, with particular focus on the advances of microbial studies in this area. We also proposed the future research prospective for the Wudalianchi mineral water. To better protect and utilize the Wudalianchi mineral water, it was recommended that a green eco-agriculture practice in reducing chemical fertilizers should be adapted in the surrounding farms of Wudalianchi. Along with the development of tourism and recuperation resources, it is necessary to establish a framework of pollution risk assessment and control, and strictly reduce potential emerging pollutants to eco-geological environment.

[Odorants Removal and Microbial Characteristics in Treatment of Micro-polluted Source Water with Biological Powdered Activated Carbon-Ultrafiltration Combined Process]

The odorants in simulated micro-polluted source water were removed by the Biological Powdered Activated Carbon-Ultrafiltration (BPAC-UF) combined process, and variations of microorganisms in the combined process were discussed. Compared with the conventional process of coagulation and sedimentation, BPAC-UF combined process had better performance in controlling odorants in micro-polluted source water. The average removal rates of dimethyl trisulfide, 2-methylisoborneol and β-ionone reached up to 77.51%, 65.86% and 98.43%, respectively. The process was more adaptable to raw water shock load. The carbon tank which had much more microbial biomass than other areas was determined to be the main unit for removing odorants. The biomass changed smoothly in the carbon tank, while the removal of odorants in raw water was stable in the process.