Enhancing biomass conservation and enzymatic hydrolysis of sweet sorghum bagasse by combining pretreatment with ensiling and NaOH.

Lignocellulosic pretreatment is an important stage in biomass utilization, which usually requires high input. In this study, a low-cost method using combined ensiling and NaOH was developed for lignocellulosic pretreatment. Sweet sorghum bagasse (SSB) was ensiled for 21 days and then treated with diluted NaOH (0%, 1%, and 2%) for fermentation. The results showed that the application of Lactobacillus plantarum (L) reduced fermentation losses of the silages, mainly low water-soluble carbohydrate (WSC) and ammonia nitrogen loss. Meanwhile, the application of Lactobacillus plantarum and ensiling enzyme (LE) promoted lignocellulosic degradation, as evidenced by low neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin (ADL), and hemicellulosic (HC) contents. The dominant bacterial genera were Lactobacillus, uncultured_bacterium_f_Enterobacteriaceae, and Pantoea after silage, which corresponded to the higher lactic acid and acetic contents and lower pH. The reducing sugar yields of SSB increased after combined pretreatment of silage and NaOH and were further enhanced by the 2% NaOH application, as evidenced by the high reducing sugar yield and microstructure damage, especially in the L-2% NaOH group and the LE-2% NaOH group, in which the reducing sugar yields were 87.99 and 94.45%, respectively, compared with those of the no additive control (CK)-0 NaOH group. Therefore, this study provides an effective method for SSB pretreatment to enhance biomass conservation.

Application of biochar in microbial fuel cells: Characteristic performances, electron-transfer mechanism, and environmental and economic assessments.

Biochar is a by-product of thermochemical conversion of biomass or other carbonaceous materials. Recently, it has garnered extensive attention for its high application potential in microbial fuel cell (MFC) systems owing to its high conductivity and low cost. However, the effects of biochar on MFC system performance have not been comprehensively reviewed, thereby necessitating the evaluation of the efficacy of biochar application in MFCs. In this review, biochar characteristics were outlined based on recent publications. Subsequently, various applications of biochar in the MFC systems and their probable processes were summarized. Finally, proposals for future applications of biochar in MFCs were explored along with its perspectives and an environmental evaluation in the context of a circular economy. The purpose of this review is to gain comprehensive insights into the application of biochar in the MFC systems, offering important viewpoints on the effective and steady utilization of biochar in MFCs for practical application.

[Progress in microbial remediation of antibiotic-residue contaminated environment].

In recent years, antibiotics have been widely used in animal husbandry, aquaculture and the medication in China. Many antibiotics are discharged into the environment, resulting in dramatic increase of antibiotic residues in domestic water and soil. Residues of different antibiotics in the environment change the microbial structure, which is extremely harmful to the ecological environment and humans. Therefore, remediation of antibiotic contamination is significantly important. Studies have shown that some microorganisms can degrade and utilize antibiotics, and thus have good application prospects on bioremediation of antibiotic contamination. However, little is known about the microbial degradation mechanism of antibiotics. This article summarizes the removal of antibiotics by antibiotic-degrading strains and bacterial flora in recent ten years, and the methods of using microbial flora to treat antibiotic residues. The future prospect of using microbial remediation to reduce antibiotic residues in the environment has also been discussed.

Occurrence of Extended-Spectrum and AmpC-Type ß-Lactamase Genes in Escherichia coli Isolated from Water Environments in Northern Thailand.

Sixty-eight cefotaxime-resistant Escherichia coli isolates were recovered from different water environments in Northern Thailand. Isolates were mostly resistant to ceftazidime and aztreonam (>90%). The most common extended-spectrum ß-lactamase-encoding gene was blaCTX-M-group 1 (75%) followed by blaCTX-M-group 9 (13.2%). The co-existence of blaCTX-M and AmpC-type ß-lactamase genes was detected in 4 isolates (5.9%). Two E. coli isolates carrying blaCTX-M from canal and river water samples belonged to the phylogenetic group B2-ST131, which is known to be pathogenic. This is the first study on blaCTX-M and blaCMY-2-carrying E. coli and the emergence of ST131 from water environments in Thailand.

Millerozyma phetchabunensis sp. nov., a novel ascomycetous yeast species isolated from Nam Nao forest soil in Thailand, and the transfer of Pichia koratensis to the genus Millerozyma.

A total of 4 strains (DR2-4, DW2-1, DS2-1 and DS3-1) of undescribed ascomycetous yeast, isolated from Nam Nao forest soil, were identified as a novel species in the genus Millerozyma. The D1/D2 sequences of the strains differed from the closely related species Millerozyma acaciae and Pichia koratensis by 1.2% (7 nucleotide substitutions) and 1.4% (8 nucleotide substitutions). Phenotypically, all the novel strains were identical, but differed from M. acaciae and P. koratensis by a variety of phenotypic characteristics. Based on phenotypic and phylogenetic data, these four yeast strains were assigned to a single novel species in the genus Millerozyma and the name Millerozyma phetchabunensis sp. nov. is proposed. In addition, we also propose the transfer of P. koratensis, which was placed in the Millerozyma clade based on the analysis of the D1/D2 and ITS sequences, to the genus Millerozyma as M. koratensis comb. nov.

Tetrapisispora namnaonensis sp. nov., a novel ascomycetous yeast species isolated from forest soil of Nam Nao National Park, Thailand.

Twenty-one strains of a novel ascomycetous yeast species were isolated from soil collected in three kinds of natural forest, namely a dry dipterocarp forest, a mixed deciduous forest and a pine forest, in Nam Nao National Park, Phetchabun province, Thailand. The strains formed asci containing one to four ovoid to reniform ascospores, assimilated glucose, galactose and glycerol, fermented glucose and galactose vigorously and contained ubiquinone Q-6, indicating that they belonged to the genus Tetrapisispora. A comparative analysis of the small subunit rDNA (SSU rDNA) and the D1/D2 domain of the large subunit rDNA (LSU rDNA) of all available sequences for ascomycetous yeasts confirmed that the strains were phylogenetically related to the genus Tetrapisispora. All strains had identical nucleotide sequences in the D1/D2 domain of the LSU rDNA and differed from the nearest species, Tetrapisispora arboricola IFO 10925(T), by 6.4% nucleotide substitutions. The strains differed from Tetrapisispora arboricola by the ability to assimilate D-gluconic acid, the inability to grow on 50% glucose medium, the nuclear DNA base composition and deliquescent asci. The strains were differentiated from the other four species of Tetrapisispora on the basis of trehalose assimilation, the ability to grow on 50% glucose or 10% NaCl plus 5% glucose, vitamin requirement, the nuclear DNA base composition and the type of ascus. Based on the characteristics mentioned above, the strains are recognized as a single novel species of the genus Tetrapisispora and the name Tetrapisispora namnaonensis sp. nov. is proposed. The type strain is TN1-01(T) (=TISTR 5828(T)=JCM 12664(T)=CBS 10093(T)).