Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.

Boric acid is a water soluble chemical preservative that has been used as food preservative by some local manufacturers. This chemical is used to preserve food products such as noodle and fish ball in order to inhibit the growth of microorganism, so that the preserved food can stay fresh and longer....

Full description

Saved in:

Bibliographic Details
Main Author:	Ang, Swi See
Format:	Thesis
Language:	English English
Published:	2011
Subjects:	Boric acid Paecilomyces Biological assay
Online Access:	http://psasir.upm.edu.my/id/eprint/26999/1/IB%202011%2016R.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-upm-ir.26999
record_format	uketd_dc
spelling	my-upm-ir.269992022-01-26T05:47:25Z Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii. 2011-04 Ang, Swi See Boric acid is a water soluble chemical preservative that has been used as food preservative by some local manufacturers. This chemical is used to preserve food products such as noodle and fish ball in order to inhibit the growth of microorganism, so that the preserved food can stay fresh and longer. However, its usage is prohibited by government of Malaysia as boric acid is considered harmful to human health if consumed in a considerably large quantity. Therefore, the detection method for boric acid is important. To date, no study has been performed to detect boric acid by using microorganism as sensing element. Hence, this study was aimed to develop a simple, fast and environmental friendly bioassay system incorporated with Paecilomyces variotii as bioreceptor for detection of boric acid in food. This detection system was based on the measurement of the changes of β-glucosidase produced by the microorganisms in response to the presence of boric acid. The changes of β-glucosidase concentration were assayed spectrophotometerically and correlated to the concentration of boric acid. In this system, P. variotii was grown in cellobiose medium for two days before its mycelia were entrapped in calcium alginate in bead form. In order to optimize the best condition for β-glucosidase production, the important factors such as initial pH, temperature, amount of cell loading, concentration of sodium alginate and calcium chloride were determined. The system was found to show optimum β-glucosidase production when 2% (w/v) sodium alginate and 0.25 Molar calcium chloride were used. Maximum enzyme production was also obtained with initial pH 7 and temperature 45 °C, using 6% (w/v) mycelia after three hours of incubation. By using these optimum operating conditions, a lower detection limit of 0.037% (w/v) was obtained from a linear range of 0% to 0.215% (w/v). The reproducibility of the system was acceptable with an observed relative standard deviation of 4.96% (n=10) and 4.81% (n=10) in the presence of 0.2% (w/v) boric acid and absence of boric acid, respectively. The bioassay system was then applied to determine boric acid in fish ball and the results of recovery ranging from 61% – 86% were recorded for boric acid spiked at different concentrations of boric acid from 0.05% to 0.20% (w/v). The developed microbial bioassay system not only represents a simple, inexpensive and environmental friendly alternative for determination of boric acid, but also offers a new idea and promising approach to detect boric acid. Boric acid Paecilomyces Biological assay 2011-04 Thesis http://psasir.upm.edu.my/id/eprint/26999/ http://psasir.upm.edu.my/id/eprint/26999/1/IB%202011%2016R.pdf application/pdf en public masters Universiti Putra Malaysia Boric acid Paecilomyces Biological assay Institute of Bioscience English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Boric acid Paecilomyces Biological assay
spellingShingle	Boric acid Paecilomyces Biological assay Ang, Swi See Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.
description	Boric acid is a water soluble chemical preservative that has been used as food preservative by some local manufacturers. This chemical is used to preserve food products such as noodle and fish ball in order to inhibit the growth of microorganism, so that the preserved food can stay fresh and longer. However, its usage is prohibited by government of Malaysia as boric acid is considered harmful to human health if consumed in a considerably large quantity. Therefore, the detection method for boric acid is important. To date, no study has been performed to detect boric acid by using microorganism as sensing element. Hence, this study was aimed to develop a simple, fast and environmental friendly bioassay system incorporated with Paecilomyces variotii as bioreceptor for detection of boric acid in food. This detection system was based on the measurement of the changes of β-glucosidase produced by the microorganisms in response to the presence of boric acid. The changes of β-glucosidase concentration were assayed spectrophotometerically and correlated to the concentration of boric acid. In this system, P. variotii was grown in cellobiose medium for two days before its mycelia were entrapped in calcium alginate in bead form. In order to optimize the best condition for β-glucosidase production, the important factors such as initial pH, temperature, amount of cell loading, concentration of sodium alginate and calcium chloride were determined. The system was found to show optimum β-glucosidase production when 2% (w/v) sodium alginate and 0.25 Molar calcium chloride were used. Maximum enzyme production was also obtained with initial pH 7 and temperature 45 °C, using 6% (w/v) mycelia after three hours of incubation. By using these optimum operating conditions, a lower detection limit of 0.037% (w/v) was obtained from a linear range of 0% to 0.215% (w/v). The reproducibility of the system was acceptable with an observed relative standard deviation of 4.96% (n=10) and 4.81% (n=10) in the presence of 0.2% (w/v) boric acid and absence of boric acid, respectively. The bioassay system was then applied to determine boric acid in fish ball and the results of recovery ranging from 61% – 86% were recorded for boric acid spiked at different concentrations of boric acid from 0.05% to 0.20% (w/v). The developed microbial bioassay system not only represents a simple, inexpensive and environmental friendly alternative for determination of boric acid, but also offers a new idea and promising approach to detect boric acid.
format	Thesis
qualification_level	Master's degree
author	Ang, Swi See
author_facet	Ang, Swi See
author_sort	Ang, Swi See
title	Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.
title_short	Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.
title_full	Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.
title_fullStr	Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.
title_full_unstemmed	Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.
title_sort	development of a microbial bioassay system for detection of boric acid using paecilomyces variotii.
granting_institution	Universiti Putra Malaysia
granting_department	Institute of Bioscience
publishDate	2011
url	http://psasir.upm.edu.my/id/eprint/26999/1/IB%202011%2016R.pdf
_version_	1747811569096458240

Development of a microbial bioassay system for detection of boric acid using Paecilomyces variotii.

Similar Items