Characterization of the Rumen-Mimetic Continuous Cultivation System for Volatile Fatty Acid Production from Lignocellulosic Biomass
Hitosi Agematu,
Jun Watanabe,
Takehiko Takahashi
Issue:
Volume 6, Issue 1, March 2021
Pages:
1-8
Received:
31 January 2021
Accepted:
7 February 2021
Published:
23 February 2021
Abstract: The rumen-mimetic continuous cultivation system (RMS) was used to produce volatile fatty acids (VFAs), such as acetic, propionic, and butyric acids, from lignocellulosic biomass. Typical 12 species of ruminal bacteria were detected in the culture broth cultivated by RMS using species-specific PCR assay. These species are known to be cellulolytic, hemicellulolytic, proteolytic, amylolytic, and lipolytic bacteria and methanogens. Therefore, RMS was characterized to be ruminal fermentation like the digestive system of roughage in the rumen of cattle. Using RMS, the ruminal bacteria were continuously cultivated for 120 days to produce VFAs. The yield of total VFAs from 20–50 μm rice straw was 167% higher than that from 300–1000 μm rice straw. However, the productivity was not increased by pulverization of the substrate. The yield and productivity of acetic acid from 20–50 μm rice straw were 0.147 g/g and 34.8 mg/L/h, respectively, and those of propionic acid were 0.104 g/g and 24.6 mg/L/h, respectively. The selectivity (P/A ratio) of acetic and propionic acid production from microcrystalline cellulose at pH 6.5 and 7.0 were 0.83±0.07 and 0.31±0.03, respectively. The ruminal bacteria could not continue to produce VFAs at pH 6.0. The yield and productivity of acetic acid from microcrystalline cellulose at pH 6.5 were 0.234 g/g and 51.7 mg/L/h, respectively, and those of propionic acid were 0.223 g/g and 49.3 mg/L/h, respectively. This study proposes that in order to increase the productivity of RMS, it is necessary to increase the ruminal bacterial biomass by recycling biomass (flocs) using a settling tank.
Abstract: The rumen-mimetic continuous cultivation system (RMS) was used to produce volatile fatty acids (VFAs), such as acetic, propionic, and butyric acids, from lignocellulosic biomass. Typical 12 species of ruminal bacteria were detected in the culture broth cultivated by RMS using species-specific PCR assay. These species are known to be cellulolytic, h...
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Application of Multiplex Molecular Assays in the Diagnosis of Acute Respiratory Infectious Diseases
Issue:
Volume 6, Issue 1, March 2021
Pages:
9-20
Received:
10 February 2021
Accepted:
2 March 2021
Published:
10 March 2021
Abstract: Acute respiratory tract infections (ARTIs) are the most common diseases worldwide and an important cause of morbidity and mortality. Upper and lower respiratory tract infections are caused by a variety of bacterial, viral, and fungal pathogens. Clinical diagnosis of respiratory tract infections is challenging because of indistinguishable symptoms. Laboratory diagnosis is performed by serology, culture, electron microscopy, and immunological antigen detection assays. These conventional diagnostic procedures are time consuming, lack sensitivity, require special laboratory setup, and well-trained staff. In the clinical laboratories, multiplex molecular nucleic acid amplification tests (NAATs) are continuously replacing conventional diagnostic methods. This review summarizes and discusses the availability, clinical use, advantages and disadvantages of multiplex molecular methods in the detection and identification of ARTI pathogens. The multiplex molecular assays can simultaneously detect 20 or more bacterial and viral pathogens and have the advantage of increased sensitivity, specificity, and rapid turn-around time. These assays are helpful in syndromic based testing in high risk patient population, particularly those who are immunocompromised, hospitalized and/or seen in the emergency department. Limitations of multiplex molecular assays include inability to detect all the possible pathogens that can be present, not being able to differentiate between asymptomatic carriers and true infections, and sometimes results are difficult to interpret. Furthermore, additional testing may be required as these assays do not provide any information regarding antimicrobial susceptibility profile. Rapid and accurate diagnosis of respiratory tract infections leads to better treatment decisions, reduction in the further diagnostic procedures, length of hospital stay, better infection control measures, and associated healthcare costs.
Abstract: Acute respiratory tract infections (ARTIs) are the most common diseases worldwide and an important cause of morbidity and mortality. Upper and lower respiratory tract infections are caused by a variety of bacterial, viral, and fungal pathogens. Clinical diagnosis of respiratory tract infections is challenging because of indistinguishable symptoms. ...
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Screening and Identification of Flocculant Producing Bacteria and Its Application in Wastewater
Sha Sha Zhang,
Ming Li,
Li Fang Wang,
Xiu Dong Wang,
Jian Feng Xu
Issue:
Volume 6, Issue 1, March 2021
Pages:
21-27
Received:
4 March 2021
Accepted:
17 March 2021
Published:
26 March 2021
Abstract: Background: with the increasingly serious global water pollution, industrial and agricultural wastewater treatment is becoming more and more important. Flocculant precipitation is the first process in wastewater treatment. One of the keys to achieve efficient water purification is to add microbial flocculant with excellent performance. Objective: the research of high-efficiency and non-toxic microbial flocculant for wastewater treatment has increasingly become important in environmental protection. Method: CMC-Na medium and dilute iodine staining was used to separate and screen flocculant producing bacteria. The distribution of flocculant activity and the effect of different types of wastewater treatment were studied. Results: the flocculant producing strain 71-1 separate from ruminant feces was identified as Cellulosimicrobiums sp. The flocculating rate of MBF-P71 was 97.83%, which had obvious degradation effect on COD value of pig farm manure water and ship port sewage. The removal rates of cod were 66.95% and 46.68% respectively. Conclusion: MBF-P71 has the advantages of good flocculation effect, low production cost, high efficiency and low dosage. It has a good development and application prospect for wastewater treatment.
Abstract: Background: with the increasingly serious global water pollution, industrial and agricultural wastewater treatment is becoming more and more important. Flocculant precipitation is the first process in wastewater treatment. One of the keys to achieve efficient water purification is to add microbial flocculant with excellent performance. Objective: t...
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