Removal of 2,4,5-trichlorophenol by bacterial isolates from the secondary sludge of pulp and paper mill

Biodegradation of furfuryl alcohol by indigenous Bacillus species of industrial effluent-contaminated sites: estimation, biokinetics and toxicity assessment of bio-transformed metabolites

Furfuryl alcohol (FA) and other furanic compounds have garnered considerable attention in the quest for sustainable alternatives. FA-based resins have been used in various sectors that entail the release of FA into the environment. Hence, to ensure sustainability in this scenario, devising a dependable approach to its degradation is imperative. Given the crucial role of bacterial strains in the biodegradation of various organic pollutants, this study investigates the microbial degradation of FA, using bacterial strains isolated from sites that are constantly exposed to industrial waste. Three potential isolates were identified as B. paramycoides, B. cereus, and B. tequilensis by 16S rRNA gene sequencing. At a concentration of 300 µg/ml, these isolates demonstrated efficient FA degradation; 60-70% (at 300 µg/ml FA) and 50-60%, (at 500 µg/ml FA). Fourier-transform infrared (FTIR) spectroscopy and High-Performance Liquid Chromatography (HPLC) analysis further supported the result that the bacterial isolates consumed FA as the carbon source. Liquid chromatography-mass spectrometry (LC-MS) facilitates the detection of the major metabolic intermediate product in which FA gets transformed. The prominent peaks at 113 and 119 m/z obtained in the MS spectra of the degraded FA samples indicated the possibility of the conversion of FA into furoic acid or levulinic acid. The phytotoxicity bioassay findings revealed the non-toxic nature of the bio-transformed products as compared to pure FA. This investigation presents the initial documentation of the FA degradative potential of Bacillus strains, thereby augmenting the understanding of the prospective implementation of Bacillus species in industrial waste treatment projects.

Acclimation of 2-chlorophenol-biodegrading activated sludge and microbial community analysis

Using glucose as cosubstrate, activated sludge that could effectively biodegrade 40 mg/L 2-chlorophenol was successfully domesticated in sequencing batch reactors. To acclimate the sludge, 2-chlorophenol was increased stepwise from 0 to 40 mg/L. High-throughput sequencing revealed that the microbial community richness increased during the first 5 days of acclimation to 5 mg/L 2-chlorophenol and then decreased after another 20 days as 2-chlorophenol was increased. The original sludge obtained from a water resource recovery facility had the highest microbial diversity. As the acclimation continued further, community richness and diversity both increased, but they decreased again, significantly, when 2-chlorophenol reached 40 mg/L. Saccharibacteria_norank, Bacillus, Saprospiraceae_uncultured, and Lactococcus were the dominant bacteria. Bacillus and Pseudomonas were the main known chlorophenol-degrading bacteria. WCHB1-60_norank, Tetrasphaera, Comamonadaceae_unclassified, and Haliangium showed poor tolerance to 2-chlorophenol. Higher bacterial tolerance to chlorophenols does not mean higher degrading capability. The degradation of chlorophenols was not positively correlated with the detected abundance of known 2-chlorophenol-degrading bacteria. PRACTITIONER POINTS: Activated sludge that could effectively biodegrade 40 mg/L 2-chlorophenol was successfully domesticated using glucose as cosubstrate in sequencing batch reactors. Saccharibacteria_norank, Bacillus, Saprospiraceae_uncultured, and Lactococcus were the dominant bacteria. Bacillus and Pseudomonas were the main known chlorophenol-degrading bacteria detected in this study. The degrading capability and tolerance of bacteria to chlorophenols were relatively independent and the degradation of chlorophenols may be the synergistic effect of various bacteria.

Acclimation of 2-chlorophenol Biodegrading Activated Sludge and Microbial Community Analysis

Taking glucose as co-substrate, the activated sludge which could effectively biodegrade 2-chlorophenol (2-CP) of 40 mg/L　was successfully domesticated after acclimation for 49 days in sequencing batch reactors. High-throughput sequencing (HTS) analysis revealed that the community richness initially increased for 5 days and then decreased after another 20 days with the increase of 2-CP. The original sludge obtained from water resource recovery facility had the highest diversity. At the beginning of acclimation, the community diversity decreased. With the acclimation going on, both richness and diversity of community increased, but decreased significantly when the concentration of 2-CP was increased to 40 mg/L. Saccharibacteria_norank, Bacillus, Saprospiraceae_uncultured and Lactococcus were the dominant bacteria detected in this study. Bacillus and Pseudomonas were the main chlorophenol-degrading bacteria. WCHB1-60_norank, Tetrasphaera, Comamonadaceae_unclassified and Haliangium had lower tolerance to 2-CP. Higher bacterial tolerance to CPs does not mean higher degrading capability. The degradation of CPs was not positively correlated with the abundance of known 2-CP degrading bacteria detected in this study.