ABSTRACT
Carnauba (Copernicia prunifera) is a Brazilian palm tree used for wax production, which usually generates a large amount of waste. This work evaluated the carnauba waste for cellulase and xylanase production using Trichoderma reesei CCT2768 through a solid-state fermentation (SSF). Carnauba waste was used in its crude form (C-IN), pretreated (C-P) with alkaline hydrogen peroxide (AHP), and also recycled after the SSF process (C-PR). C-IN, C-P, and C-PR were characterized by XRD, FTIR, and SEM. Cellulase and xylanase production was performed by SSF for 72 h, and the enzymatic extracts obtained were mixed each other in different concentrations. FPase, CMCase, and xylanase activities were determined. Trichoderma reesei CCT-2768 has shown high performance to produce cellulases and xylanases. Total cellulase, CMCase, and ß-glycosidase presented a highest activity when C-PPR1 (25% of C-PR and 75% of C-P) was used as a carbon source, with yield of 2.85 U/g, 41.21 U/g, and 2.80 U/g, respectively. The highest xylanase production was achieved when only the pretreated carnauba waste (C-P) was used, with an enzyme activity of 224.93 U/g. Carnauba has shown a promising carbon source capacity to induce the production of cellulolytic and xylanolytic enzymes by using T. reesei CCT2768, promoting the circular and ecofriendly economy, as well as a cost reduction, of the production process of these enzymes.
Subject(s)
CellulaseABSTRACT
BACKGROUND: In the presence of anti-thyroglobulin antibodies (TgAb), serum thyroglobulin (Tg) might be underestimated. Therefore, the American Thyroid Association does not recommend serum Tg after thyroid hormone withdrawal or recombinant human thyrotropin administration (stimulated Tg) and diagnostic whole-body scanning (DxWBS) in TgAb-positive patients who have serum Tg values while on thyroxine (Tg-on-T4) of <1 ng/mL. The objective of this study was to determine, in patients with differentiated thyroid cancer (DTC) who appeared to be free of disease after surgery and ablative treatment, but who had positive serum TgAb, the value of performing DxWBS and obtaining serum Tg under stimulated Tg conditions. METHODS: There were 121 women and 15 men in the study. By selection criteria, all of them had total thyroidectomy with apparent complete tumor resection, remnant ablation with (131)I (1.1-5.5 GBq), and a post-(131)I therapy WBS that were negative for ectopic (131)I uptake. On assessment 8-12 months after (131)I ablation, their clinical exam needed to be normal, their Tg-on-T4 needed to be <1 ng/mL, and the test for TgAb needed to be positive. Stimulated Tg, neck ultrasound (US), and DxWBS were obtained from all patients. Patients with stimulated Tg >1 ng/mL without disease on US and DxWBS were evaluated by other imaging methods. RESULTS: In 10 (7.3%) patients, stimulated Tg was >1 ng/mL. The DxWBS revealed metastases in two of these patients, and other imaging methods showed disease in three others. Stimulated Tg was <1 ng/mL in 126 patients. DxWBS revealed metastases in three of these patients, and US detected lymph node metastases in four with a negative DxWBS. Tg stimulation combined with DxWBS revealed evidence for disease in 13 (9.5%) patients. When excluding patients with a positive US, DxWBS revealed metastases in four patients, and stimulated Tg of >1 ng/mL led to detection of persistent disease by other imaging methods in two more patients. CONCLUSIONS: Performing stimulated Tg and DxWBS at the same time seems to be useful after initial therapy in DTC patients with TgAb who do not otherwise appear to have persistent disease, even when US is negative.
