4 research outputs found
Evaluation of the potential of free and immobilized thermophilic bacterial enzymes in the degradation of agro-industrial wastes
Agro-industrial wastes are potential starting materials for the production of
useful value-added compounds, including prebiotic oligosaccharides. In this
paper, we evaluated the potential of thermophilic bacterial pectin- and
xylan-degrading recombinant enzymes for the degradation of the
agro-industrial wastes: apple pomace, wheat straw, wheat bran and distillers
grains. For the immobilization of pectate lyase and xylanase, three different
supports were used. The effect of enzyme immobilization was analyzed in terms
of enhanced thermostability and activity against these wastes. For xylanase,
the highest thermostability was achieved by immobilization on Sepabeads
EC-EP/M. The best activity against bran and grains was obtained by
immobilization on Sepabeads EC-HA/M. For pectate lyase, the highest
thermostability was achieved by immobilization on Sepabeads EC-EP/M, however,
activity against apple pomace pectin was slightly reduced by this
immobilization. The length of oligosaccharides produced by both free and
immobilized enzymes was also determined
Identification of proteins involved in starch and polygalacturonic acid degradation using LC/MS
Characterization of antimicrobial activity of culturable bacteria isolated from Krubera-Voronja Cave
In the present study we aimed to perform the first analysis of antimicrobial activity of bacteria isolated from Krubera-Voronja Cave, with the main focus on their activity against Grampositive bacteria, including Gram-positive pathogens. Using five different media, in total 874 heterotrophic cultures were isolated from water and sediment samples collected in Krubera-Voronja Cave at a depth from 220 m to 1640 m. 14.0% of all isolates demonstrated antibacterial activity against Gram-positive and Gram-negative test microorganisms. Our results show that this percentage was not uniform; it increased with the sampling depth and was the highest in the lower part of the cave. 24 isolates were active exclusively against Gram-positive test strains Micrococcus luteus and Bacillus thuringiensis. Two isolates, namely strains 1350R2-TSA30-6 and 1410WF1-TSA30-2, were chosen for the further work because of the high and comparable activity against both Gram-positive test microorganisms. It was determined that both strains belong to the family Bacillaceae in phylum Firmicutes. The detailed bioactivity analysis of these two Gram-positive strains revealed the different mixtures of volatile compounds with antibacterial activity. The main antibacterial compounds of the strain 1350R2-TSA30-6 are pyrrolopyrazines pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro- 3-(2-methylpropyl)- and pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl)-. The main antibacterial compound of the strain 1410WF1-TSA30-2 is 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester. Mixtures of the volatile antimicrobial compounds of both strains were antagonistic against Gram-positive strains isolated from Krubera-Voronja Cave, and their activity against Gram-positive pathogenic bacteria substantially differed
Identification of proteins involved in starch and polygalacturonic acid degradation using LC/MS
Plant biomass in the form of cheap wastes, such as straw, corn stalks, wood chips, sawdust, bagasse, pomace, etc.,
is abundant throughout the world. To convert these wastes into the useful value-added compounds microbial enzymes are the
preferred choice. In this paper, we identify enzymes involved in the degradation of starch and polygalacturonic acid using liquid
chromatography/mass spectrometry based analysis. We analysed total protein from soil and compost samples. Extracellular
proteins from enrichment cultures were analysed in parallel and used as controls in the sample preparation and identification of
proteins. In general, both protein sequence coverage and the number of identified peptides were higher in the samples obtained
from the enrichment cultures than from the total protein from soil and compost. The influence of the nature of gel (zymography
vs. SDS/polyacrylamide) was negligible. Thus, starch and polygalacturonic acid degradation associated proteins can be directly
excised from the zymograms without the need to align zymograms with the SDS/polyacrylamide gels. A range of starch and
polygalacturonic acid degradation associated enzymes were identified in both total protein samples and extracellular proteins from
the enrichment cultures. Our results show that proteins involved in starch and polygalacturonic acid degradation can be identified by
liquid chromatography/mass spectrometry from the complex protein mixtures both with and without cultivation of microorganisms