Abstract:
TL7 -6, a cellulolytic alkaliphilic thermophilic anaerobic bacterial enrichment culture was
accumulated from shrimp farm at Bangkhuntien area, Thailand. This enrichment culture has high
efficient cellulose powder degrading activity that could degrade completely within 5 days at 55 C. It
comprised three kinds of colonies forming as transparent, creamy and yellowish spot types.
Identification of this culture with nucleotide sequencing that all of them are Clostridia genus. The
temperature and initial pH for growth of the bacterial enrichment culture were 45-55 C, with an
optimum temperature at 50 C and pH 8.0-9.5, with an optimum pH at 8.0.
This bacterial enrichment culture produced crude enzyme when cultivated in basal medium
containing cellulose powder as a carbon source at pH 9.5 and 50?C. Activities of avicelase,
carboxymethyl cellulase (CMCase), mannanase and xylanase. The temperature and pH optima of
the cellulase activity were 50?C and 8.0, while thermal and pH stability were in wide ranges of 37-
60?C (more than 70%) and pH 4.0-11.0 (more than 80%), respectively. Native-PAGE of crude
enzyme showed 12 protein bands, whereas SDS-PAGE exhibited at least 29 protein bands.
Zymogram analysis revealed 22 protein bands with the sizes of 250,242,235,206, 188, 177, 166,
143, 135, 127, 117, 107, 97, 96, 90, 87, 82, 71, 68, 64, 59 and 52 kDa having cellulase activity and
five active bands of xylanase activity with the sizes of 213, 206, 194, 188 and 71 kDa. Furthermore,
the crude enzyme were found to adhere to avicel and insoluble xylan. The cellulase and xylanase
enzymes had binding ability to avicel at 63% and 55% and insoluble xylan at 29% and 48%,
respectively. In the hydrolysis of raw lignocellulosic substrance by crude enzyme at pH 9.5 and 50
?C, com hull was found to be the most susceptible to enzyme for hydrolysis, followed by rice husk,
rice straw, com cob and sugarcan bagasse, respectively.
The activity and stability of crude enzyme was examined during the washing in the presence of
detergents, Vanish (Ll), Essence (L2), Breeze Excel (L3), Breeze Power Turbo (P4), Attack Easy
(P5), Omo (P6) and Pao Silver Nano (P7). The crude enzyme shows highest efficiency of approx.
85% in the presence of Breeze Power Turbo (P4). To evaluate the cellulase action in improving the
washing efficiency of the detergents, pieces of white cotton cloth soiled with tea stain were washed
with each detergent in the presence of the crude enzyme from TL 7 -6. Our results showed that, the
combination of crude enzyme and Breeze Power Turbo (P4) has the maximum increase in bright
value (L * value) from 60.55 to 66.95 and the maximum decrease in yellow value (b* value) from
20.82 to 12.86 when compared to the washing with only water, enzyme and detergent. Therefore,
the properties of alkaline cellulase have a great potential for application in detergent industry.