Simultaneous effect of cathode potentials and magnetite concentrations on methanogenesis of acetic acid under different ammonia conditions

Electromethanogenesis (EM) is a system that facilitates direct interspecies electron transfer (DIET) in anaerobic digestion (AD) by providing an external power supply to favor desired reactions. Substrates of AD commonly contain ammonia (NH3) as biodegradation product of nitrogen-rich compounds that can deteriorate the stability of AD process. Optimized cathode potential (VCAT) and magnetite (Mag) concentration ([Mag]) are expected to improve AD efficiency in the presence of NH3. Response surface analysis with central composite face-centered design was used in this study to investigate the effect of VCAT and [Mag] under different total ammonia nitrogen concentration ([TAN]). Highest cumulative methane production was achieved at VCAT = -737.4 mV, [Mag] = 18.2 mM, and [TAN] = 1.5 g/L; highest acetate degradation rate was achieved at VCAT = 757.6 mV, [Mag] = 21.4 mM, and [TAN] = 1.5 g/L. The study demonstrated that VCAT promotes either microbial growth or electrochemical NH3 removal. A Shift from acetoclastic to hydrogenotrophic pathway was also observed by the increase of hydrogenotrophic methanogen populations at the end of experiment. This study is beneficial for process control of AD under different NH3 conditions.

COMPONENT COMPOSITION OF THE BIODEGRADATION PRODUCT OF FALLEN LEAVES BY BASIDIOMY-CETES PLEUROTUS PULMONARIUS (STRAIN PP-3.2)

Today, plant waste, including fallen poplar leaves (litter), are a promising raw material for the production of useful products using bioconversion, such as protein feed additives. The aim of this study was to study the component composition of the products obtained as a result of the bioconversion of leaf litter. The strain PP-3.2 Pleurotus pulmonarius (Fr.) Quél. In the process of substrate conversion, strain PP-3.2 primarily utilizes extractives and easily hydrolyzable polysaccharides, the amount of which decreases by 44 and 36%, respectively. The total content of polysaccharides is reduced by 20%, lignin substances - 9.4%. The loss of substrate mass based on leaf litter was 23%. The product obtained after cultivation contains 28% protein. Analysis of the amino acid composition of the protein showed a high rate of phenylalanine with tyrosine (115), threonine (117.5), valine (110) and isoleucine (105%). Also, the biodegradation product has a high content of glutamic and aspartic acids (11.2 and 25.3% of the total amino acids, respectively). The levels of cadmium, lead and copper revealed as a result of studies do not exceed the maximum permissible concentrations established by the veterinary department. At the same time, there is a high content of iron (166.0 μg/kg) and zinc (256.7 mg/kg) in the feed product. The digestibility of the product is 54%, the content of nucleic substances is up to 0.3%. Thus, the results obtained show the possibility of using the product of the conversion of poplar fallen leaves as a protein feed additive.

Polyethylene Terephthalate Degradation by Microalga Chlorella vulgaris Along with Pretreatment

The current research explored the potential of microalgal species Chlorella vulgaris and Pretreatment to remediate plastic waste. It was concluded from the results that Pretreatment had a marked effect on the cracking and alteration of plastic polymer, which helped to grow microbial species on the cracked surface as evident by Compound Microscopy (CM), Scanning Electron Microscopy (SEM), and Fourier Transformed Infrared Spectroscopy (FTIR) analysis. FTIR data also supported the notion that in the absence of any pretreatment, the microbial species were not able to mediate plastic biodegradation efficiently as the nature of functional groups was different in the presence and absence of Pretreatment. GCMS analysis revealed that the microbial specie could produce the biodegradation products which were likely to be found in the structure of PET, including alkanes ester, fatty acids, benzoic acid, and aromatics and the most toxic product of biodegradation is Bis (2-Ethyl hexyl phthalate), which is the biodegradation product of toxic ingredient of plastics that is phthalic acid.

Human Biomonitoring of Glyphosate Exposures: State-of-the-Art and Future Research Challenges

Glyphosate continues to attract controversial debate following the International Agency for Research on Cancer carcinogenicity classification in 2015. Despite its ubiquitous presence in our environment, there remains a dearth of data on human exposure to both glyphosate and its main biodegradation product aminomethylphosphonic (AMPA). Herein, we reviewed and compared results from 21 studies that use human biomonitoring (HBM) to measure urinary glyphosate and AMPA. Elucidation of the level and range of exposure was complicated by differences in sampling strategy, analytical methods, and data presentation. Exposure data is required to enable a more robust regulatory risk assessment, and these studies included higher occupational exposures, environmental exposures, and vulnerable groups such as children. There was also considerable uncertainty regarding the absorption and excretion pattern of glyphosate and AMPA in humans. This information is required to back-calculate exposure doses from urinary levels and thus, then compare these levels with health-based guidance values. Back-calculations based on animal-derived excretion rates suggested that there were no health concerns in relation to glyphosate exposure (when compared with EFSA acceptable daily intake (ADI)). However, recent human metabolism data has reported as low as a 1% urinary excretion rate of glyphosate. Human exposures extrapolated from urinary glyphosate concentrations found that upper-bound levels may be much closer to the ADI than previously reported.

Metabolite Identification from Biodegradation of Congo Red by Pichia sp.

Azo dyes are commonly used in textile and paper industries. However, its improper disposal often results in polluting water bodies. Azo dyes can cause adverse health effects because of its carcinogenic properties. Various methods to remove azo dyes from water have been proposed, including biological methods such as biosorption and biodegradation. Biosorption and biodegradation were done by using bacteria, yeast or mold. In general, yeasts have some advantages for azo dyes degradation due to its faster growth compared to mold and better resistance against unfavorable environment compared to bacteria. Previously, we observed that yeast Pichia sp. have the ability to degrade Congo red, an azo dye. However, information regarding biodegradation of azo dyes by Pichia sp. are still limited. Therefore, in this study, we showed degradation of Congo red by Pichia sp. crude enzyme extract obtained from separating Pichia cells from medium by centrifugation, followed by identification of its biodegradation products. Biodegradation product was separated from enzyme by ethyl acetate and then Gas Chromatography-Mass Spectroscopy (GC-MS) method was employed to identify biodegradation product. Chromatogram results of GC-MS showed that Congo red were degraded into various products such as biphenyl, naphthalene and smaller molecules with 94 m/z and 51 m/z. These results suggest involvement of azo reductase and laccase-like enzymes which cleaves azo bonds and oxidize the dye molecules to smaller molecules. This study implies the use of Pichia sp. as a bioremediation agent for the removal of azo dyes. Keywords: Biodegradation, Congo red, Pichia sp., metabolite identification, GC-MS

Efficacy of Bacillus subtilis ANSB060 Biodegradation Product for the Reduction of the Milk Aflatoxin M1 Content of Dairy Cows Exposed to Aflatoxin B1

This study was conducted to determine the effect of Bacillus subtilis ANSB060 biodegradation product (BDP) in reducing the milk aflatoxin M1 (AFM1) content of dairy cows fed a diet contaminated with aflatoxin B1 (AFB1). Twenty-four Chinese Holstein cows (254 ± 19 d in milk; milk production 19.0 ± 1.2 kg d−1) were assigned to three dietary treatments, as follows: (1) control diet (CON), consisting of a basal total mixed ration (TMR); (2) aflatoxin diet (AF), containing CON plus 63 μg of AFB1 kg−1 of diet dry matter; and (3) aflatoxin diet plus BDP (AF + BDP), containing AF plus BDP at 0.2% of diet dry matter. The experiment lasted 12 days, including an AFB1-dosing period from days one to eight, followed by a clearance period from days nine to twelve. Milk samples were collected on days 2, 4, 6, and 8–12, and the plasma was sampled on day 9, before morning feeding. Short-term AFB1 exposure did not affect the milk production and composition. The plasma biochemical indices, except for lactic dehydrogenase (LDH), were also not changed by the AFB1 intake. The plasma LDH level was significantly elevated (p < 0.05) following dietary treatment with AFB1, while no significant difference was observed between the AF + BDP and CON treatments. Adding BDP to the AFB1-contaminaed diet resulted in a significant reduction in AFM1 concentration (483 vs. 665 ng L−1) in the milk, AFM1 excretion (9.14 vs. 12.71 μg d−1), and transfer rate of dietary AFB1 to milk AFM1 (0.76 vs. 1.06%). In conclusion, the addition of BDP could be an alternative method for reducing the dietary AFB1 bioavailability in dairy cows.