Waste frying oil hydrolysis and lipase production by cold-adapted Pseudomonas yamanorum LP2 under non-sterile culture conditions.

Non-sterile culture technique is currently used in some microbial processes. However, there is no study on the use of this technique in the production of microbial lipases and hydrolysis of waste frying oils. This study was conducted to hydrolyse waste frying oils and produce lipase under non-sterile culture conditions using locally isolated cold-adapted bacteria. Of 75 bacterial isolates, the psychrotolerant Pseudomonas yamanorum LP2 (Genbank number: KU711080) was determined to have the highest lipase activity. It was found that a combination of restricted nutrient availability, low temperature and high inoculum volume prevented microbial contaminants under non-sterile conditions. The most favourable parameters for lipase production under both sterile and non-sterile conditions were 15°C temperature, pH 8, 30 mL/L inoculum volume, 40 mL/L waste frying oil concentration, 10 mL/L Tween-80 and 72 h incubation time. The maximum lipase activities in sterile and non-sterile media were determined as 93.3 and 96.8 U/L, respectively. The present process designed for enzyme production and waste oil hydrolysis can reduce the cost of cultivation medium as well as energy consumption and workload. The potential of cold-adapted bacteria to produce lipase and hydrolyse waste oils under non-sterile culture conditions was first tested in the current study.

Genome-based classification of Calidifontibacillus erzurumensis gen. nov., sp. nov., isolated from a hot spring in Turkey, with reclassification of Bacillus azotoformans as Calidifontibacillus azotoformans comb. nov. and Bacillus oryziterrae as Calidifontibacillus oryziterrae comb. nov.

A novel Gram-stain-positive, rod-shaped, endospore-forming, motile, aerobic bacterium, designated as P2T, was isolated from a hot spring water sample collected from Ilica-Erzurum, Turkey. Phylogenetic analyses based on 16S rRNA gene sequence comparisons affiliated strain P2T with the genus Bacillus, and the strain showed the highest sequence identity to Bacillus azotoformans NBRC 15712T (96.7 %). However, the pairwise sequence comparisons of the 16S rRNA genes revealed that strain P2T shared only 94.7 % sequence identity with Bacillus subtilis subsp. subtilis NCIB 3610T, indicating that strain P2T might not be a member of the genus Bacillus. The digital DNA-DNA hybridization and average nucleotide identity values between strain P2T and B. azotoformans NBRC 15712T were 19.8 and 74.2 %, respectively. The cell-wall peptidoglycan of strain P2T contained meso-diaminopimelic acid. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an aminophospholipid, five unidentified phospholipids and two unidentified lipids while the predominant isoprenoid quinone was MK-7. The major fatty acids were iso-C15 : 0 and iso-C16 : 0. The draft genome of strain P2T was composed of 82 contigs and found to be 3.5 Mb with 36.1 mol% G+C content. The results of phylogenomic and phenotypic analyses revealed that strain P2T represents a novel genus in the family Bacillaceae, for which the name Calidifontibacillus erzurumensis gen. nov., sp. nov. is proposed. The type strain of Calidifontibacillus erzurumensis is P2T (=CECT 9886T=DSM 107530T=NCCB 100675T). Based on the results of the present study, it is also suggested that Bacillus azotoformans and Bacillus oryziterrae should be transferred to this novel genus as Calidifontibacillus azotoformans comb. nov. and Calidifontibacillus oryziterrae comb. nov., respectively.

Bacillus pasinlerensis sp. nov., a thermophilic bacterium isolated from a hot spring in Turkey.

A Gram-reaction-positive, endospore-forming bacterium, designated strain P1T, was isolated from water samples collected from Pasinler Hot Spring and characterized using a polyphasic approach to clarify its taxonomic position. Strain P1T was found to have chemotaxonomic and morphological characteristics consistent with its classification in the genus Bacillus. The strain shared the highest 16S rRNA gene sequence identity values with Bacillus thermolactis R-6488T (97.6 %) and Bacillus kokeshiiformis MO-04T (97.2 %) and formed a distinct clade with both type strains in the phylogenetic trees based on 16S rRNA gene sequences. Strain P1T could grow optimally at 55 °C and in the presence of 2 % NaCl. The organism was found to contain meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The predominant menaquinone was determined to be MK-7. The major cellular fatty acids were identified as iso-C15 : 0, iso-C17 : 0 and anteiso-C17 : 0. Based upon the consensus of phenotypic and phylogenetic analyses, strain P1T represents a novel species of the genus Bacillus, for which the name Bacillus pasinlerensis sp. nov. is proposed. The type strain is P1T (=DSM 107529T=CECT 9885T=NCCB 100674T).

A novel endo-ß-1,4-xylanase from Pediococcus acidilactici GC25; purification, characterization and application in clarification of fruit juices.

A novel extracellular xylanase was purified and characterized from Pediococcus acidilactici GC25 (GenBank number: MF289522). The purification was 4.6-fold with a yield of 43.61% through acetone precipitation, Q-Sepharose, and CM-Sepharose ion change chromatography. The molecular weight of the enzyme was 48.15 kDa, and the optimum pH and temperature were 7.0 and 40 °C, respectively. The maximum activity was observed between 20 and 50 °C. Although it was active within a wide pH range (pH 2.0-9.0), it retained over 85% of its activity after 24 h incubation; and over 70% of its activity after 168 h incubation in neutral and alkaline pH. It was observed that the enzyme showed high stability with K+, Ba2+, Cd2+, Co2+, Sr2+, Mg2+, Ca2+, Al3+, Zn2+, and Ni2+ ions. The Km and Vmax for the xylanase were 3.10 mg mL-1 and 4.66 U/mg protein, respectively. It was determined that treatment of different fruit juices with P. acidilactici GC25 xylanase improved the clarification. The highest increase in the reducing sugar amount and decrease in the turbidity was 24.47 ±â€¯1.08 and 21.22 ±â€¯0.58 for peach juice at 0.15 U/mL enzyme concentration. These results showed that the xylanase purified from P. acidilactici GC25 may have a wide potential in biotechnological processes of the food and baking industry.