The effect of lignin containing natural substrates corn-cob, coir-dust, saw-dust, wheat straw and bagasse particles on the extracellular secretion of laccase in the liquid culture growth medium of Pleurotus sajor-caju MTCC 141 has been studied. The culture conditions for maximum secretion of laccase by Pleurotus sajor-caju MTCC 141 have been optimized. Homogeneous preparation of laccase from the culture filtrate of the fungus has been achieved using ammonium sulphate precipitation, anion exchange chromatography on DEAE and gel filtration chromatography on Sephadex G-100. The purified enzyme preparation gave a single protein band in SDS-PAGE analysis indicating a molecular weight of 90 kD. The enzymatic characteristics Km, kcat, pH and temperature optima of the purified laccase have been determined using 2, 6-dimethoxyphenol as the substrate and have been found to be 35μmol/L, 0.30 min-1, 4.5 and 37℃ respectively. The Km values for the other substrate like catechol, m-cresol, pyrogallol and syringaldazine have also been determined which were found to be 216 μmol/L, 380 μmol/L, 370 μmol/L and 260 μmol/L respectively.

Background: Opioids administered as bolus doses or continuous infusions are widely used by anesthesiologists worldwide for major and day care surgeries. Opioid-free anesthesia is a multimodal anesthesia and analgesia technique that does not use opioid drugs, thereby benefitting patients from opioid-related adverse effects. In this study, we compared the postoperative analgesic requirements of patients scheduled for elective laparoscopic cholecystectomy under opioid-free and opioid-based anesthesia. Methods: This study included 88 patients aged 18–60 years with American Society of Anesthesiologists physical status 1 and 2 who underwent elective laparoscopic cholecystectomy. Participants were randomly divided into two groups with forty-four participants in each group. The opioid-free anesthesia group was administered an intravenous bolus of ketamine and dexmedetomidine, whereas the opioid-based group was administered fentanyl with conventional general anesthesia. The primary outcome was to compare the total amount of fentanyl consumed by both groups during the 6 h postoperative period following extubation. Episodes of postoperative nausea and vomiting (PONV) and vital signs were noted throughout the postoperative period to analyze the secondary outcomes. Results: Both the groups had similar demographic characteristics. The opioid-free group required less postoperative analgesia within the first 2 h (61.4 ± 17.4 vs. 79.0 ± 19.4 of fentanyl, P < 0.001), which was statistically significant. However, fentanyl consumption was comparable between the groups at the sixth postoperative hour (opioid-free group 152 ± 28.2 vs. opioid group 164 ± 33.4, P = 0.061). Compared with 4.5% of the participants in the opioid-free group, 34% of those in the opioid-based group developed moderate PONV. Conclusions The opioid-free anesthesia technique in patients undergoing laparoscopic cholecystectomy reduced the requirement of analgesia in the first two hours of the postoperative period and was associated with decreased PONV.