| Summary: | Currently in Malaysia, most wastes are disposed into poorly managed systems
with little or no pollution protection measures. Large amounts of wastes such as
textiles are generated through hospitals and health care centers. However, the
improper management of these abundantly generated wastes may pose an
environmental pollution problems and fire hazard. Cotton textile is a potential
biomass for bioethanol production. Subcritical water (Sub-CW) hydrolysis was
investigated as an alternative technology for the recycling of cotton textile waste
for current health care waste management. The aim of this study is to investigate
the possibility of complete conversion of cotton textile waste to ethanol via Sub-
CW hydrolysis and fermentation. Sub-CW was carried out to facilitate the
hydrolysis of cellulose component in cotton textile (cotton 75%+polyester 25%).
The study was divided into two parts; (i) To evaluate the subcritical water
parameters such as temperature and time to achieve maximum yield of sugars.
(ii) Fermentation of the hydrolysate obtained from Sub-CW hydrolysis to ethanol.
Under Sub-CW conditions of temperature (140 °C - 350 °C), reaction time (1-10
min) and water to cotton ratio (3:1) revealed that cotton textile treated at 280 °C
for 4 min, was optimal for maximizing yield of sugar, which was 0.213 g/g-dry
sample. The quantitative analysis by HPLC showed that the soluble
carbohydrates in the water phase were mainly composed of glucose. The
obtained glucose concentration, 702 mg/L was then fermented at 36 °C for 24
hours by Saccharomyces cerevisae (yeast) to ethanol. Maximum yield of ethanol
production was 0.105 g/g glucose, which was 17.7% of theoretical yield.
Hydrolysis with Sub-CW showed the potential to decompose the cotton textile
into simple sugar while keeping sugar degradation to minimal phase and the
possibility of complete conversion of cotton textile waste to ethanol via Sub-CW
and fermentation.
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