Selection and characterization of mannanase-producing bacteria useful for the formation of prebiotic manno-oligosaccharides from copra meal |
| |
Authors: | Sudathip Titapoka Suttipun Keawsompong Dietmar Haltrich Sunee Nitisinprasert |
| |
Institution: | (1) Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand;(2) Department of Food Science and Technology, Division of Food Biotechnology, BOKU – University of Natural Resources and Applied Life Sciences, Vienna, Austria |
| |
Abstract: | In order to select bacterial strains effectively secreting mannanase activity for the production of prebiotic mannooligosaccharides,
a two-step screening procedure was performed. Enriched cultures from isolation medium containing copra meal were primary screened
on an isolation agar medium containing 1% locust bean gum (LBG), which resulted in 48 mannanase-producing bacterial isolates
with significant clearing zones on the mannan-containing agar. However, only nine isolates showed appreciable mannanase activities
against copra meal in their culture supernatants (0.054–0.185 U/mg of protein) as determined in a standard assay based on
the detection of reducing sugars released from this substrate. The isolates CW2-3 and ST1-1 displayed the highest activity
against LBG and copra meal, respectively. Copra mannan hydrolysates that were obtained by using crude mannanase from these
nine isolates were further used for a secondary screening towards a growth-enhancing activity on Lactobacillus reuteri and inhibitory activity against Escherichia coli as well as Salmonella Enteritidis, resulting in 0.09–2.15 log CFU/ml enhancing activity and low inhibitory activity of 0.46–1.78 log CFU/ml as
well as 0.37–1.72 log CFU/ml, respectively. The hydrolysate of CW2-3 mannanase showed the highest enhancing activity of 2.15 log
CFU/ml while isolate ST1-1 was most effective with respect to growth inhibition against E. coli E010 and S. Enteritidis S003 with 0.76 and 1.61 log CFU/ml, respectively. Based on morphological, physical, biochemical and genetics
properties, isolates CW2-3 and ST1-1 were identified as Klebsiella oxytoca and Acinetobacter sp., respectively. Crude mannanase activity from these two strains was characterized preliminarily. The pH optima of mannanase
activity from Klebsiella oxytoca CW2-3 and Acinetobacter sp. ST1-1 were 7 and 6, respectively. The enzymes were stable at 4°C over a pH range of 3–6 and 3–10, respectively. |
| |
Keywords: | Mannanase Copra mannan hydrolysate Prebiotic Klebsiella oxytoca Acinetobacter sp |
本文献已被 SpringerLink 等数据库收录! |
|