Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade mi...Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade microorganism and chemical synthesis for the production of AA.Several studies reported that lactic acid bacteria (LAB) have the capability of producing AA owing to their well-established proteolytic system and amino acid biosynthesis genes.Hence,the objectives of this study were to explore the extracellular proteolytic activity of LAB isolated from various Malaysian fermented foods and their potential to produce AA extracellularly as feed supplements.Results:All the studied LAB isolates were versatile extracellular protease producers,whereby extracellular protease activities were detected from acidic to alkaline pH (pH 5,pH 6.5,pH 8) using qualitative and quantitative proteolytic assays.The highest proteolytic activity at pH 5 (15.76 U/mg) and pH 8 (19.42 U/mg) was achieved by Lactobacillus plantarum RG14,while Lactobacillus plantarum RS5 exhibited the highest proteolytic activity of 17.22 U/mg at pH 6.5.As for the results of AA production conducted in de Man,Rogosa and Sharpe medium and analysed by high pressure liquid chromatography system,all LAB isolates were capable of producing an array of AA.Generally,Pediococcus sp.showed greater ability for AA production as compared to Lactobacillus sp.Moreover,the studied LAB were able to produce a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.P.pentosaceus TL-3 recorded the highest methionine and threonine productivity of 3.72 mg/L/h and 5.58 mg/L/h respectively.However,L.plantarum I-UL4 demonstrated a lysine productivity of 1.24 mg/L/h,while P.acidilactici TP-6 achieved up to 1.73 mg/L/h of tryptophan productivity.Conclusion:All the 17 studied LAB isolates possessed versatile extracellular proteolytic system and have vast capability of producing various amino acids including a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.Despite AA production was strain dependent,the studied LAB isolates possessed vast potential and can be exploited further as a bio-agent or an alternative amino acids and bioactive peptide producers.展开更多
Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence anal...Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence analysis of 16S ribosomal RNA gene. Some of the microbes have also been recommended as feed additives for improving the overall growth or production of animals. Rumen bacteria which have potential application in animal feed stuffs were isolated and characterized in this experiment. Isolation was carried out from the rumen of cattle (Bos taurus) using techniques of serial dilutions and repeated tubing of the selectively enriched microbial cultures by using the specific media for rumen bacteria. All the isolates were then screened for in vitro gas production and cellulase enzyme activity and four superior isolates were selected and characterized. There were 18.00% to 23.00% increases in gas production on addition of these isolates to the rumen fluid of cattle and there was better cellulase enzyme activity. Two isolates were identified as Butyrivibrio fibrisolvens, one isolate as Streptococcus species and one isolate as Clostridium aminophilum. This indicated that, these isolates are superior and may have potential to be used as microbial feed additive in ruminants if fed in higher quantity.展开更多
Red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera, Curculionidae), is considered one of the most damaging insect pests of date palms in the Kingdom of Bahrain. Large scale infestation of RPW to da...Red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera, Curculionidae), is considered one of the most damaging insect pests of date palms in the Kingdom of Bahrain. Large scale infestation of RPW to date palm trees leads to excessive feeding activity of the RPW larvae, which is carried out by microorganisms present within RPW and producing a wet fermenting material inside the trunk. Culture dependent-bacteria were isolated from feeding waste and identified by the sequencing of the 16S rRNA gene using 8F and 1492R universal primers. Among the culture-dependent isolated bacteria, 80% were identified by comparing 16S rRNA gene sequence in NCBI database, using BLAST program in GenBank. 85% of the identified bacteria were Gram-positive while the rest of them were Gram-negative. A high abundance of bacteria were from the Bacillaceae family and sixteen different species of Bacillus were identified in comparison with NCBI GenBank. The 16S rRNA gene sequences of identified bacterial strains have been submitted to GenBank. The phylogenetic relationship was studied using 16S rRNA gene sequences, the Gram-negative bacteria came in one clade while Gram-positive different Bacillus sp. and strains showed evolutionary closeness to each other and accordingly, they came in one major clade under three different sub-clades in the phylogenetic tree. The findings of new Bacillus strains in the natural habitat of the date plam trees in the Kingdom of Bahrain, pledge a vast area of research on RPW bio-control research arena.展开更多
Bioaerosol emissions from animal feeding operation (AFO) facilities are of increasing interest due to the magnitude of the emissions and their potential health effect on local communities. There is limited information...Bioaerosol emissions from animal feeding operation (AFO) facilities are of increasing interest due to the magnitude of the emissions and their potential health effect on local communities. There is limited information about fate and transport of AFO bioaerosol emissions. In this study, concentrations of airborne bacteria and fungi were measured at four ambient stations in four wind directions surrounding an egg production farm through winter, spring and summer using Andersen six-stage samplers. Mean concentrations of ambient bacteria and fungi ranged from 8.7 × 102 CFU m-3 to 1.3 × 103 CFU m-3 and from 2.8 × 102 CFU m-3 to 1.4 × 103 CFU m-3, respectively. Ambient bacterial concentrations were not significantly different over the seasons, while ambient fungal concentrations were the highest in summer and the lowest in winter. There were significant differences between downwind and upwind bacterial concentrations (p < 0.0001). Downwind bacterial and fungal concentrations responded differently to the influencing factors. Bacterial concentrations were quadratically correlated with wind vector (combined effects of wind speed and direction) and emission rate, were positively correlated with temperature, and were negatively correlated with solar radiation. Fungal concentrations were positively correlated with temperature, RH, and emission rate, and were negatively correlated with wind vector.展开更多
基金The Long-Term Research Grant(LRGS)of the Ministry of Education of Malaysia supported this work
文摘Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade microorganism and chemical synthesis for the production of AA.Several studies reported that lactic acid bacteria (LAB) have the capability of producing AA owing to their well-established proteolytic system and amino acid biosynthesis genes.Hence,the objectives of this study were to explore the extracellular proteolytic activity of LAB isolated from various Malaysian fermented foods and their potential to produce AA extracellularly as feed supplements.Results:All the studied LAB isolates were versatile extracellular protease producers,whereby extracellular protease activities were detected from acidic to alkaline pH (pH 5,pH 6.5,pH 8) using qualitative and quantitative proteolytic assays.The highest proteolytic activity at pH 5 (15.76 U/mg) and pH 8 (19.42 U/mg) was achieved by Lactobacillus plantarum RG14,while Lactobacillus plantarum RS5 exhibited the highest proteolytic activity of 17.22 U/mg at pH 6.5.As for the results of AA production conducted in de Man,Rogosa and Sharpe medium and analysed by high pressure liquid chromatography system,all LAB isolates were capable of producing an array of AA.Generally,Pediococcus sp.showed greater ability for AA production as compared to Lactobacillus sp.Moreover,the studied LAB were able to produce a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.P.pentosaceus TL-3 recorded the highest methionine and threonine productivity of 3.72 mg/L/h and 5.58 mg/L/h respectively.However,L.plantarum I-UL4 demonstrated a lysine productivity of 1.24 mg/L/h,while P.acidilactici TP-6 achieved up to 1.73 mg/L/h of tryptophan productivity.Conclusion:All the 17 studied LAB isolates possessed versatile extracellular proteolytic system and have vast capability of producing various amino acids including a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.Despite AA production was strain dependent,the studied LAB isolates possessed vast potential and can be exploited further as a bio-agent or an alternative amino acids and bioactive peptide producers.
文摘Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence analysis of 16S ribosomal RNA gene. Some of the microbes have also been recommended as feed additives for improving the overall growth or production of animals. Rumen bacteria which have potential application in animal feed stuffs were isolated and characterized in this experiment. Isolation was carried out from the rumen of cattle (Bos taurus) using techniques of serial dilutions and repeated tubing of the selectively enriched microbial cultures by using the specific media for rumen bacteria. All the isolates were then screened for in vitro gas production and cellulase enzyme activity and four superior isolates were selected and characterized. There were 18.00% to 23.00% increases in gas production on addition of these isolates to the rumen fluid of cattle and there was better cellulase enzyme activity. Two isolates were identified as Butyrivibrio fibrisolvens, one isolate as Streptococcus species and one isolate as Clostridium aminophilum. This indicated that, these isolates are superior and may have potential to be used as microbial feed additive in ruminants if fed in higher quantity.
文摘Red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera, Curculionidae), is considered one of the most damaging insect pests of date palms in the Kingdom of Bahrain. Large scale infestation of RPW to date palm trees leads to excessive feeding activity of the RPW larvae, which is carried out by microorganisms present within RPW and producing a wet fermenting material inside the trunk. Culture dependent-bacteria were isolated from feeding waste and identified by the sequencing of the 16S rRNA gene using 8F and 1492R universal primers. Among the culture-dependent isolated bacteria, 80% were identified by comparing 16S rRNA gene sequence in NCBI database, using BLAST program in GenBank. 85% of the identified bacteria were Gram-positive while the rest of them were Gram-negative. A high abundance of bacteria were from the Bacillaceae family and sixteen different species of Bacillus were identified in comparison with NCBI GenBank. The 16S rRNA gene sequences of identified bacterial strains have been submitted to GenBank. The phylogenetic relationship was studied using 16S rRNA gene sequences, the Gram-negative bacteria came in one clade while Gram-positive different Bacillus sp. and strains showed evolutionary closeness to each other and accordingly, they came in one major clade under three different sub-clades in the phylogenetic tree. The findings of new Bacillus strains in the natural habitat of the date plam trees in the Kingdom of Bahrain, pledge a vast area of research on RPW bio-control research arena.
文摘Bioaerosol emissions from animal feeding operation (AFO) facilities are of increasing interest due to the magnitude of the emissions and their potential health effect on local communities. There is limited information about fate and transport of AFO bioaerosol emissions. In this study, concentrations of airborne bacteria and fungi were measured at four ambient stations in four wind directions surrounding an egg production farm through winter, spring and summer using Andersen six-stage samplers. Mean concentrations of ambient bacteria and fungi ranged from 8.7 × 102 CFU m-3 to 1.3 × 103 CFU m-3 and from 2.8 × 102 CFU m-3 to 1.4 × 103 CFU m-3, respectively. Ambient bacterial concentrations were not significantly different over the seasons, while ambient fungal concentrations were the highest in summer and the lowest in winter. There were significant differences between downwind and upwind bacterial concentrations (p < 0.0001). Downwind bacterial and fungal concentrations responded differently to the influencing factors. Bacterial concentrations were quadratically correlated with wind vector (combined effects of wind speed and direction) and emission rate, were positively correlated with temperature, and were negatively correlated with solar radiation. Fungal concentrations were positively correlated with temperature, RH, and emission rate, and were negatively correlated with wind vector.
