ABSTRACT
Aims@#Lytic polysaccharide monooxygenase (LPMO) is an enzyme capable of cleaving glycoside bonds of recalcitrant polysaccharides through an oxidative mechanism. LPMO activity, in synergy with hydrolytic enzymes, increases the production of monomer sugars from the biodegradation of lignocellulose. This study was aimed at evaluating actinomycete S2 strain LPMO activity based on the release of xylose as one of reducing sugar and hydrogen peroxide (H2O2) in the course of lignocellulosic biodegradation. @*Methodology and results@#The oxidation activity of LPMO from actinomycete S2 strain was measured by using the substrate of Avicel supplemented with ascorbic acid and copper ions (Cu2+) to identify its effect on the release of xylose as one of reducing sugar. The optimum incubation time for the LPMO production was also conducted. Further, H2O2 quantitative analysis was performed as by-product of LPMO activity and 16S rRNA gene sequence of actinomycete S2 strain were subsequently determined. We found that supplementation of 1 mM ascorbic acid and 0.2 mM Cu2+ increased xylose as one of reducing sugar production by up to 5-fold from 255.03 to 1290 μg/mL after an optimal incubation period of 6 days. Based on H2O2 production, the LPMO activity of actinomycete S2 strain was 0.019 ± 0.001 U/mL. There is likelihood that LPMO activity derived from actinomycete S2 strain has a synergistic effect with the activity of other lignocellulose-degrading enzymes. This actinomycete showed 99% similarity to the 16S rRNA gene sequence of Streptomyces avermitilis strain EAAG80. @*Conclusion, significance, and impact of study@#LPMO enzyme activity from actinomycete S2 strain as determined by the production of reducing sugar and H2O2 was greatly increased by supplementation with ascorbic acid as an electron donor and Cu2+ ions. To the best of our knowledge, this is the first elucidation of LPMO activity from an indigenous Indonesian actinomycete.
ABSTRACT
Aims@#Hypercholesterolemia which is an elevated blood cholesterol level that considered as a major risk factor for cardiovascular disease, which is the leading cause of death in many countries. Therefore, lowering the cholesterol level is important to prevent the disease. Lactic acid bacteria (LAB) group are often used as probiotics for their healthpromotion which include cholesterol-lowering effect. The purpose of this study was to evaluate the potency of Pediococcus pentosaceus as probiotic that could reduce cholesterol. @*Methodology and results@#All P. pentosaceus strains were able to survive in acid conditions and in the presence of 0.3% bile salts. These strains had antimicrobial activity against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and Salmonella typhimurium ATCC 14028. The LAB were also sensitive to chloramphenicol and showed autoaggregation and coaggregation ability. Pediococcus pentosaceus E5, E7, and E8 were able to remove cholesterol with the highest activity showed by P. pentosaceus E7 (49.00 ± 2.83%). Dead cells and resting cells of P. pentosaceus E5, E7, and E8 (6-22%) also able to reduce the cholesterol but not as effectively as growing cells. Cholesterol lowering is often associated with bile salt hydrolase (BSH) enzyme activity, however none of the isolates were found BSH positive in this study. @*Conclusion, significance and impact of study@#The present study suggests that P. pentosaceus E7 has beneficial probiotic properties which can be exploited for probiotic product with cholesterol-lowering effect.
Subject(s)
Pediococcus pentosaceusABSTRACT
Aims: The study focused on screening, identification and characterization of mannanolytic actinomycetes isolated from soil and leaf litter samples obtained from several sites in Indonesia. Methodology and results: A total of 337 isolates of actinomycetes isolated from soil and leaf litter samples collected from various areas in Indonesia were screened for their mannanolytic activity. Mannanase activity was analysed using locus bean gum (LBG) as the substrate. The strain ID06-0379 displayed significant mannanase activity. The strain ID06- 0379 was analysed for its mannanase activity by determining the rate of enzyme production when cultured in the presence of palm kernel cake (PKC) as a substrate. The highest mannanase activity from ID06-0379 was 4.40 U/mL at 5% PKC concentration at 5 days incubation. Chemotaxonomic and phenotypic characterisation of mannanolytic actinomycete was done and the strain ID06-0379 contained meso-diaminopimelic acid, and madurose was the diagnostic sugar in whole cell sugar. The polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, and hydroxy-phosphatidylethanolamine. The predominant menaquinone of strain ID06-0379 was MK-9(H4). The major cellular fatty acids were C16:0 (31.47%), cis9-C16:1 (15.23%) and iso-C16:0 (10.84%), and the G+C content of the DNA was 71.7 mol%. Phylogenetic analysis based on the 16S rDNA sequences revealed that strain ID06- 379 was closely related to species of Nonomuraea jabiensis A4036T with 99% nucleotide similarity. Conclusion, significance and impact study: The results from this study revealed that the mannanolytic actinomycete strain ID06-379 belongs to the genus Nonomuraea that closely related to N. jabiensis A4036T . Mannanase production using agricultural waste such as palm kernel cake may contribute to the development and utilisation of biomass bioconversion processes. Keywords: Indonesian actinomycetes, mannanase enzyme, locus bean gum, palm kernel cake, Nonomuraea sp. ID06- 0379.