scholarly journals The granulation-inhibiting principles from Eucalyptus globulus Labill. III. The structures of euglobal-III,-IVb and -VII.

1982 ◽  
Vol 30 (6) ◽  
pp. 1964-1973 ◽  
Author(s):  
MUTSUO KOZUKA ◽  
TOKUNOSUKE SAWADA ◽  
EIJI MIZUTA ◽  
FUMIKO KASAHARA ◽  
TOSHIO AMANO ◽  
...  
Keyword(s):  
Eucalyptus Globulus

Prebleaching of eucalypt kraft pulp with OP stages: Effect of an acid pretreatment or chelation step

TAPPI Journal ◽  
2012 ◽  
Vol 11 (6) ◽  
pp. 31-38
Author(s):  
TATIANA M. PÓVOAS ◽  
DINA A.G. ANGÉLICO ◽  
ANA P.V. EGAS ◽  
PEDRO E.G. LOUREIRO ◽  
LICÍNIO M. GANDO-FERREIRA ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Comparative Evaluation ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Acid Pretreatment ◽  
High Brightness ◽  
Pulp Viscosity ◽  
Brightness Reversion

We conducted a comparative evaluation of different treatments for the bleaching of eucalypt kraft pulps beginning with OP stages. The treatments tested were (1) an acid chelation stage with DTPA (OQP sequence); (2) a hot acid stage (AOP sequence); and (3) a chelant addition into the alkaline oxygen stage ((OQ)P and A(OQ)P sequences). The latter strategy was also studied for environmental reasons, as it contributes to the closure of the filtrate cycle. The OQP sequence leads to the highest brightness gain and pulp viscosity and the lowest peroxide consumption caused by an efficient metals control. Considering that the low biodegradability of the chelant is a problem, the A(OQ)P sequence is an interesting option because it leads to reduced peroxide consumption (excluding OQP) while still reaching high brightness values and similar brightness reversion to OQP prebleaching, with only a viscosity loss of 160 dm3/kg. Therefore, a hot acid stage could be considered when a separate acid Q stage is absent in a prebleaching sequence of Eucalyptus globulus kraft pulps involving OP stages.

Safety Evaluation of Eucalyptus globulus Essential Oils through Acute and Sub-acute Toxicity and Skin Irritation in Mice and Rats

2020 ◽  
Vol 14 (3) ◽  
pp. 187-195
Author(s):  
Berhan Mengiste ◽  
Tizazu Zenebe ◽  
Kassahun Dires ◽  
Ermias Lulekal ◽  
Awol Mekonnen ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Essential Oil ◽  
Eucalyptus Globulus ◽  
Biochemical Parameters ◽  
Skin Irritation ◽  
Toxicity Study ◽  
Subacute Toxicity ◽  
Acute Toxicity Study ◽  
Limit Test ◽  
Ointment Formulation

Background: The Eucalyptus globulus extractions have been used by the traditional healers to treat diseases in the study area. Our previous study revealed that the essential oil has antimicrobial and antifungal activity. This study determined phytochemical analysis, skin irritation, acute and subacute toxicity of Eucalyptus globulus essential oil in mice and rats. Methods: The phytochemicals were analyzed using GC-MS mass spectrometry. The acute toxicity study was determined at three dose levels of 1500 mg/kg, 1750mg/kg, and 2000 mg/kg. The essential oil limit test at a dose of 1000 mg/kg was administered to mice for 28 consecutive days for sub-acute toxicity study. The mice mortality, behavioral change, injury and other signs of illness were recorded once daily. Biochemical parameters were evaluated. Liver and kidney were analyzed for histopathological analyses. The 5% ointment formulation was applied to the rat skin to determine skin irritation effects. Results: The Eucalyptus globulus essential oil showed no effect on the mice at a dose of 1500mg/kg and below, but caused signs of toxicity and death at a dose of 1750mg/kg and above compared to the controls (p<0.05). The LD50 value was 1650 mg/kg. There was no significant difference (p > 0.05) in the body weights, gross abnormalities of the organs and biochemical parameters compared to the control at 1000 mg/kg subacute toxicity study. No histopathological changes were detected in the organs tested. The 5% ointment formulation did not show any abnormal skin reaction. Discussion: In the present study, the Eucalyptus globulus essential oil was comparable with other studies in terms of both chemical composition and its effects on sub-acute and topical application. Conclusion: This toxicity study demonstrated that Eucalyptus globulus essential oil is nontoxic at a relatively lower concentration.

Chitinase activities are induced in Eucalyptus globulus roots by ectomycorrhizal or pathogenic fungi, during early colonization

1994 ◽  
Vol 91 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Catherine Albrecht ◽  
Alain Asselin ◽  
Yves Piche ◽  
Frederic Lapeyrie
Keyword(s):  
Eucalyptus Globulus ◽  
Pathogenic Fungi

scholarly journals Effects on Lignin Redistribution in Eucalyptus globulus Fibres Pre-Treated by Steam Explosion: A Microscale Study to Cellulose Accessibility

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 507
Author(s):  
Eduardo Troncoso-Ortega ◽  
Rosario del P. Castillo ◽  
Pablo Reyes-Contreras ◽  
Patricia Castaño-Rivera ◽  
Regis Teixeira Mendonça ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Eucalyptus Globulus ◽  
Steam Explosion ◽  
Laser Scanning ◽  
Structural Changes ◽  
Micro Particles ◽  
Cellulose Accessibility ◽  
Ft Ir ◽  
Enzymatic Accessibility ◽  
Physical And Chemical

The objective of this study was to investigate structural changes and lignin redistribution in Eucalyptus globulus pre-treated by steam explosion under different degrees of severity (S0), in order to evaluate their effect on cellulose accessibility by enzymatic hydrolysis. Approximately 87.7% to 98.5% of original glucans were retained in the pre-treated material. Glucose yields after the enzymatic hydrolysis of pre-treated material improved from 19.4% to 85.1% when S0 was increased from 8.53 to 10.42. One of the main reasons for the increase in glucose yield was the redistribution of lignin as micro-particles were deposited on the surface and interior of the fibre cell wall. This information was confirmed by laser scanning confocal fluorescence and FT-IR imaging; these microscopic techniques show changes in the physical and chemical characteristics of pre-treated fibres. In addition, the results allowed the construction of an explanatory model for microscale understanding of the enzymatic accessibility mechanism in the pre-treated lignocellulose.

The impact of acid hydrolysis conditions on carbohydrate determination in lignocellulosic materials: a case study with Eucalyptus globulus bark

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ricardo Jorge Oliveira ◽  
Bruna Santos ◽  
Maria J. Mota ◽  
Susana R. Pereira ◽  
Pedro C. Branco ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Eucalyptus Globulus ◽  
Industrial Processes ◽  
Lignocellulosic Materials ◽  
Optimal Conditions ◽  
Hydrolysis Conditions ◽  
The Impact ◽  
Eucalyptus Bark

Abstract Lignocellulosic biomass represents a suitable feedstock for production of biofuels and bioproducts. Its chemical composition depends on many aspects (e.g. plant source, pre-processing) and it has impact on productivity of industrial bioprocesses. Numerous methodologies can be applied for biomass characterisation, with acid hydrolysis being a particularly relevant step. This study intended to assess the most suitable procedures for acid hydrolysis, taking Eucalyptus globulus bark as a case study. For that purpose, variation of temperature (90–120 °C) was evaluated over time (0–5 h), through monosaccharides and oligosaccharides contents and degradation. For glucose, the optimal conditions were 100 °C for 2.5 h, reaching a content of 48.6 wt.%. For xylose, the highest content (15.2 wt.%) was achieved at 90 °C for 2 h, or 120 °C for 0.5 h. Maximum concentrations of mannose and galactose (1.0 and 1.7 wt.%, respectively) were achieved at 90 and 100 °C (2–3.5 h) or at 120 °C (0.5–1 h). These results revealed that different hydrolysis conditions should be applied for different sugars. Using this approach, total sugar quantification in eucalyptus bark was increased by 4.3%, which would represent a 5% increase in the ethanol volume produced, considering a hypothetical bioethanol production yield. This reflects the importance of feedstock characterization on determination of economic viability of industrial processes.

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