Proteolytic and lipolytic potential of Pseudomonas spp. from goat and bovine raw milk

Abstract

Pseudomonas, the main genus of gram-negative microorganisms isolated from milk, is psychrotrophic, biofilm-forming, and thermo-resistant deteriorating enzyme producers. The aim of this study was to quantify Pseudomonas spp. in goat’s and cow’s milk produced in the Paraná state, Brazil, to evaluate the deteriorating activity of the isolates at mesophilic and psychrotrophic conditions and to identify, at the species level, the isolates with alkaline metalloprotease (aprX gene) production potential. Microbiological, biochemical and molecular methods were used for isolating, confirming and identifying of isolates. The mean counts were 1.6 (±6.3)x104 and 0.89(±3)x102 CFU/mL for goat and bovine milk samples, respectively, immediately after milking. Of the Pseudomonas colonies isolated from goat milk (n=60), 91.7% showed proteolytic potential when incubated at 35°C/48 h and 80% at 7°C/10 days, and lipolytic potential was observed in 95% of the isolates incubated in mesophilic and 78.3% at refrigeration conditions. From the isolates of bovine milk (n=20), 35% showed proteolytic activity only when incubated at 35°C/48 h, and lipolytic potential was observed in 25% of the isolates incubated at 7°C/10d and 35°C/48h. It was observed that 83.3% and 25% of the isolates genetically confirmed as Pseudomonas spp. of goat and bovine milk showed the potential for alkaline metalloprotease production, with the species P. azotoformans, P. koreensis, P. gessardii, P. monteilii and P. lurida being the most frequent in goat milk and P. aeruginosa the only species identified in cow milk.

Analysis of Bacterial Community level Physiological Profiling on the Fermentation of Traditional Pliek u using BIOLOG EcoPlates

“…The substrate was fermented for at least 72 hours until the substrate produced oil. Then, the substrate was dried under the sun, and the oil was separated from the 3Bio Journal of Biological Science, Technology and Management 3(1): [18][19][20][21][22][23][24][25][26][27] Edwar et Aditiawati pulp using a press machine. Sampling was done every 24 hours during fermentation stages (sample I=0 h, sample II=24 h, sample III=48 h, and sample IV=72 h).…”

“…The formation of compounds that plays a role in flavours during fermentation can occur through the metabolism of flavour precursor compounds or flavour compounds themselves by microorganisms [22]. In general, the 3Bio Journal of Biological Science, Technology and Management 3(1): [18][19][20][21][22][23][24][25][26][27] Edwar et Aditiawati compounds that play a role in flavour formation can come from groups of amino acids, phenols, and ketones [23]. Amino acids have a vital role in the formation of flavour.…”

“…P. azotoformans has previously been reported in foods such as milk and meat [25] [26]. Furthermore, P. azotoformans is also classified as proteolytic and lipolytic bacteria because it can hydrolyse proteins and lipids [27].…”

“…3Bio Journal of Biological Science, Technology and Management 3(1):[18][19][20][21][22][23][24][25][26][27] Edwar et Aditiawati…”

Draft Genome Sequence of Pseudomonas saudiphocaensis Strain AGROB56, Isolated from a Dairy Farm in New Zealand

“…They are Gram-negative bacteria, usually aerobic, but can be facultative anaerobes ( 7 – 9 ). While some Pseudomonas species can be associated with pathogenicity, some species have been applied as bioremediation agents ( 5 , 10 – 14 ), and some are known for their dairy spoilage potential, such as Pseudomonas fragi , P. lundensis , and P. fluorescens ( 15 , 16 ).…”