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Title
Anatomical morphological and chemical characterization of lignocellulosic by-products of lemon and sofia grasses obtained after recuperation of essential oils by steam distillation
Authors
HARJEET KAUR and DHARM DUTT
Received
February 26, 2012
Published
Volume 47 Issue 1-2 January-February
Keywords
lemon grass, sofia grass, morphology, chemical characterization, thermo-mechanical properties
Abstract
The lignocellulosic wastes of two oil-producing grasses, namely lemon and sofia grasses, obtained after recuperation of
citronella and geranial oils by steam distillation create environmental problems. The anatomy of these grasses has
shown that the strong sheath of sclerenchyma fibers encircling the vascular bundles provide hitherto unexploited
sources of cellulosic fibers at a time when most of the nations are searching new alternatives, because of shrinking of
forest wealth. Total fibers in lemon and sofia grasses were found to be of 37.8 and 34.61%; parenchyma and epidermal
cells amounted to 35.33 and 37.14%, and 21.64 and 23.83%, respectively. Lemon grass fibers were longer (1.09 mm)
and wider (16.3 µm), compared to sofia grass fibers (0.87 mm) with narrow diameter (14.7 µm). The Runkel ratio of
lemon (1.45) and sofia (1.52) grasses was lesser, compared to sugarcane bagasse fibers, therefore it would result in a
greater degree of fiber collapse and higher degree of conformability and would give rise to sheets of higher density.
SEM studies confirmed the rupturing of oil glands as a result of steam distillation, thereby abating the problem of mass
transfer and facilitating faster penetration of cooking liquor during pulping. α–cellulose contents were satisfactory for
lemon (44.16%) and sofia (45.55%) grasses. Due to almost similar lignin contents in lemon (17.39%) and sofia
(17.04%) grasses and to the open and loose anatomy, the pulping conditions of these grasses would be similar and with
no need for separate delignification. Thermal degradation rates for lemon and sofia grasses were of 1.02 and 0.65
mg/min, respectively, attained at 350 °C, but lemon grass contributed more to charring.
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