Ultraviolet‐radiation‐resistant isolates revealed cellulose‐degrading species of Cellulosimicrobium cellulans (UVP1) and Bacillus pumilus (UVP4)

Abstract

Abstract.Among extremophiles, microorganisms resistant to ultraviolet radiation (UVR) have been known to produce a variety of metabolites (i.e., extremolytes). We hypothesized that natural microbial flora on elevated land (hills) would reveal a variety of UVR-resistant extremophiles and polyextremophiles with modulated proteins and enzymes that had biotechnological implications. Microorganisms Cellulosimicrobium cellulans UVP1 and Bacillus pumilus UVP4 were isolated and identified using 16S rRNA sequencing, and showed extreme UV resistance (1.03 × 10 6 and 1.71 × 10 5 J/m 2 , respectively) from elevated land soil samples along with unique patterns of protein expression under UVR and non-UVR. A broad range of cellulolytic activity on carboxymethyl cellulose agar plates in C. cellulans UVP1 and B. pumilus UVP4 was revealed at varying pH, temperature, and inorganic salt concentration. Further, the microbial strain B. pumilus UVP4 showed the basic characteristics of a novel group: polyextremophiles with significance in bioenergy.

Long-Term Enrichment of Stress-Tolerant Cellulolytic Soil Populations following Timber Harvesting Evidenced by Multi-Omic Stable Isotope Probing

“…To test for the long-term effects of timber harvesting on soil decomposer populations, we performed SIP using 13 C-labeled cellulose which comprises the greatest form of carbon (~45%) in coniferous, softwood tree biomass (Keijsers et al, 2013). We expect that the warmer, drier, near-surface soil conditions in harvested plots would select for unique cellulolytic populations such as dark-septate fungi (Gallo et al, 2009) and cellulolytic bacteria adapted to hot and arid conditions (Rastogi et al, 2010; Gabani et al, 2012; Soares et al, 2012). We also expect that long-term changes in the quality and quantity of litter inputs may drive differences in cellulolytic populations, in particular in harvested plots where coarse woody debris was retained.…”

Bio-signature of Ultraviolet-Radiation-Resistant Extremophiles from Elevated Land

“…Despite the harmful effects of radiation on humans, current studies reveal different microorganisms have found ways to survive under high levels of radiation The ability of the organisms isolated in our study to withstand high dosages of UV-C radiation could help us to explore the potential benefits on Earth including bioremediation of radioactive wastes [47] and bioenergy [13] and life in extraterrestrial environments. A total of 10 different UV-C-resistant isolates were identified.…”

“…The UVR-resistant microorganisms were isolated as described by Gabani et al [13]. Briefly, the soil samples collected at the Tracy Ridge recreation area, 2245 feet above the sea level, in the Allegheny National Forest of northwestern Pennsylvania, USA in the month of August.…”

“…The UVR resistance among isolates was characterized as described by Gabani et al [13]. Briefly, the seed cultures (1%) of each isolate (OD 600 1.25) were inoculated in a glass bowl (105 x 40 mm) containing 50 mL NB medium.…”

“…The protein modulation among UVR resistant extremophiles was characterized as described by Gabani et al [13]. Briefly, total soluble protein was extracted and purified using a B-PER bacterial protein extraction reagent kit from Pierce (IL, USA) as per manufacturer's instructions from UV and non-UV exposed microorganisms.…”