Metagenomic next-generation sequencing in diagnosing Pneumocystis jirovecii pneumonia: A case report.

It remains a huge challenge for clinicians to diagnose Pneumocystis jirovecii pneumonia (PJP) by a conventional method, which leads to delay in diagnosing PJP, accounting for higher mortality in patients with rheumatoid arthritis (RA). A 69-year-old woman, who suffered from RA for years, developed acute respiratory failure. The computed tomography scan showed diffused effusion and ground glass opacity in both lungs, which could not be differentiated from interstitial pneumonia. Metagenomic next-generation sequencing (mNGS) revealed P. jirovecii in both serum and bronchoalveolar lavage fluid with reads per million (RPM) of 17 and 437, while other diagnostic tests did not detect any pathogenic microorganism. The results were verified by quantitative polymerase chain reaction (mtSSU region) against the same samples. The DNA RPM of P. jirovecii declined notably after treatment with trimethoprim/sulfamethoxazole. The patient was discharged without treatment and finally passed away. This case fully highlights the sensitivity of mNGS in early diagnosis of PJP, which is of great significance for prognosis and treatment. Nonetheless, the clinical application of mNGS is worth further standardization and normalization.

Anaerobic fermentation of peanut meal to produce even-chain volatile fatty acids using Saccharomyces cerevisiae inoculum.

In this study, the effects of inoculating Saccharomyces cerevisiae (S. cerevisiae) on the production of volatile fatty acids (VFAs) via anaerobic fermentation of organic solid waste peanut meal were investigated. At 35°C (temperature of the medium), inoculums consisting of six different S. cerevisiae-peanut meal ratios were used in sequencing batch anaerobic fermentation, and the changes in VFA, protein, glycogen, pH, NH4+, and soluble chemical oxygen demand (SCOD) levels during the fermentation process were studied. Results showed that after inoculation with S. cerevisiae, the anaerobic fermentation of peanut meal mainly produced even-chain VFAs (acetic acid and n-butyric acid); in the early stage of fermentation, inoculation of S. cerevisiae enhanced protein dissolution efficiency and degradation rate, and completely degraded soluble glycogen. The utilization ratio of the protein and soluble glycogen improved. Analysis of significant difference showed that compared to the peanut meal control, the experimental group correlated significantly with the VFAs. The VFA obtained with the inoculum: peanut meal ratio of 0.15 g g-1 was mainly acetic acid, with peak concentration of 10,797.09 mg L-1, which was 1.82 times higher than that obtained with only the peanut meal fermentation. Response surface methodology predicted that the inoculation ratio was 0.15 g g-1, and the effect of producing VFAs was the best when the fermentation time was 8.63d. The results showed that S. cerevisiae inoculation may improve VFA production and increase the proportion of even acids.

Micro-oxygen Process Improved Synthesis of PHAs with Undomesticated Excess Sludge.

Polyhydroxyalkanoates (PHAs) are a potential substitute for traditional plastics. Synthesis of PHAs using excess sludge without additional domestication as a mixed microbial culture can reduce production costs. PHAs were synthesized using excess sludge (R1) from a continuous flow system performing simultaneous nitrification/denitrification and phosphorus removal. Excess sludge (R2) from a A2O wastewater treatment plant was used as a mixed microflora culture (MMC) and the waste fermentation liquid was used as a carbon source. Results showed that with volatile fatty acid (VFA) concentrations of 430-520 mg/L (COD of 650-750 mg/L), when R1 and R2 were reacted under anaerobic conditions, the maximum generated concentrations of PHAs were 84.41 mg/g and 30.8 mg/g, respectively. When aeration volumes were 5, 10, 15, and 20 L/h, the amounts of PHAs synthesized from R1 and R2 increased by varying degrees, with the highest amount generated at 10 L/h (108.6 mg/g and 58.58 mg/g, respectively). In the process of PHA formation, ORP shows a decreasing trend. When the concentration of PHAs reaches a maximum level, ORP drops to a "valley point." Lower ORP valley points indicate a higher potential for synthesis of PHAs. Therefore, ORP can be used as a control parameter to reflect the reaction process in the micro-oxygen synthesis of PHAs.

Impact of Alkaline Pretreatment to Enhance Volatile Fatty Acids (VFAs) Production from Rice Husk.

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)-1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L-1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.