Optimization of Nutrients and Culture Conditions for Alkaline Protease Production Using Two Endophytic Micrococci: Micrococcus aloeverae and Micrococcus yunnanensis.

An endophytic species of Micrococcus was isolated from Aloe vera leaf (syn. Aloe barbadensis) and screened for protease production with five other species of Micrococcus. Data indicated that endophytic Micrococcus aloeverae AE-6 MCC 2184T and Micrococcus yunnanensis DSM 21948T showed efficient protease production potential and secreted active protease at high salt (10%), temperature (40 °C) and in wide range of pH 8-10. Unlike M. yunnanensis DSM 21948T, protease production by M. aloeverae AE-6 MCC 2184T was stringently controlled by pH. Protease induction study using different group of peptides, peptide carbohydrates and peptide macronutrient combinations showed variable response with both the organisms. Result indicated that the amount of protease was not directly related to cell biomass but it depends on nature of inducible peptides. In this study we also developed a modified agar-well assay for semi-quantitative data from large number of replicates.

Description of Micrococcus aloeverae sp. nov., an endophytic actinobacterium isolated from Aloe vera.

A yellow Gram-stain-positive, non-motile, non-endospore -forming, spherical endophytic actinobacterium, designated strain AE-6(T), was isolated from the inner fleshy leaf tissues of Aloe barbadensis (Aloe vera) collected from Pune, Maharashtra, India. Strain AE-6(T) grew at high salt concentrations [10% (w/v) NaCl], temperatures of 15-41 °C and a pH range of 5-12. It showed highest (99.7%) 16S rRNA gene sequence similarity with Micrococcus yunnanensis YIM 65004(T) followed by Micrococcus luteus NCTC 2665(T) (99.6%) and Micrococcus endophyticus YIM 56238(T) (99.0%). Ribosomal protein profiling by MALDI-TOF/MS also showed it was most closely related to M. yunnanensis YIM 65004(T) and M. luteus NCTC 2665(T). Like other members of the genus Micrococcus, strain AE-6(T) had a high content of branched chain fatty acids (iso-C15:0 and anteiso-C15:0). MK-8(H2) and MK-8 were the predominant isoprenoid quinones. Cell wall analysis showed an 'A2 L-Lys-peptide subunit' type of peptidoglycan and ribose to be the major cell wall sugar. The DNA G+C content was 70 mol%. Results of DNA-DNA hybridization of AE-6(T) with its closest relatives from the genus Micrococcus produced a value of less than 70%. Based on the results of this study, strain AE-6(T) could be clearly differentiated from other members of the genus Micrococcus. We propose that it represents a novel species of the genus Micrococcus and suggest the name Micrococcus aloeverae sp. nov., with strain AE-6(T) ( = MCC 2184(T) = DSM 27472(T)) as the type strain of the species.

Psychrophiles: A journey of hope.

Psychrophiles are organisms living in extremely cold conditions within the temperature range of -20°C to +10°C. These organisms survive in harsh environment by modulating their genetic make-up to thrive in extremely cold conditions. These cold-adaptations are closely associated with changes in the life forms, gene expression, and proteins, enzymes, lipids, etc. This review gives a brief description of the life and genetic adaptations of psychrophiles for their survival in extreme conditions as well as the bioactive compounds that are potential antimicrobials.

Constrictifilum karadense gen. et sp. nov., a new Nostocalean genus from Maharashtra, India.

A freshwater dwelling cyanobacterium (strain MKW3) was isolated from a sample collected from a water logged sugarcane field located in Malkapur, Karad, Maharashtra, India, and was characterized using a polyphasic approach. In the 16S rRNA gene phylogenetic analysis, strain MKW3 clustered with two misidentified strains-Nostoc sp. CENA239 and Calothrix sp. NIES2100. The phylogenetically related members included strains identified as Nostoc, Aulosira, Calothrix, Tolypothrix, Camptylonemopsis and Microchaete. The phylogenetic and the morphological analysis of the strain MKW3 indicated that it does not belong to any of the above mentioned genera. Furthermore, the 16S-23S ITS secondary structure analysis provided clear evidence indicating that strain MKW3 is different from Nostoc sp. CENA239 and Calothrix sp. NIES2100. Based on the morphological, phylogenetic and 16S-23S ITS secondary structure analysis we describe our strain as Constrictifilum karadense gen. et sp. nov. in accordance with the International Code of Nomenclature for algae, fungi and plants.