Geochemical and mineralogical analysis of Kashmir Cave (SMAST), Buner, Pakistan, and isolation and characterization of bacteria having antibacterial activity

Abstract

Bacterial strains having the ability to inhibit the growth of other bacteria were isolated from soil samples collected from Kashmir Smast (smast is Pushto for cave), Khyber Pakhtunkhwa, Pakistan. The study includes mineralogical and geochemical analyses of soil sample collected from the cave, so as to describe the habitat from which the microorganisms have been isolated. Total bacterial count of the soil sample was 5.25 3 10 4 CFU mL −1. Four bacterial isolates having activity against test organisms Micrococcus luteus, Klebsiella sp., Pseudomonas sp., and Staphylococcus aureus were screened out for further study. Two of the isolates were found to be Gram-positive and the other two Gram-negative. The four isolates showing antibacterial activity were identified as Serratia sp. KC1-MRL, Bacillus licheniformis KC2-MRL, Bacillus sp. KC3-MRL, and Stenotrophomonas sp. KC4-MRL on the basis of 16S rRNA sequence analysis. Although all isolates showed antibacterial activity, only Bacillus licheniformis KC2-MRL was selected for further study due to its large zone of inhibition. Antibacterial activity of B. licheniformis KC2-MRL was optimum when grown in nutrient broth adjusted to pH 5 and after 24 hours of incubation at 35 uC. The extracted antibacterial compound was stable at pH 5-7 and 40 uC when incubated for 1 hour. The strain was found resistant against cefotaxime (ctx). Atomic-absorption analysis of the soil sample collected from the cave showed high concentrations of calcium (332.938 mg kg ) compared to the control soil collected outside the cave. FTIR spectrum of the concentrated protein showed similarity to bacitracin. The antibacterial compound showed activity against both Gram-negative and positive test strains. Mineralogy of Kashmir Smast is diverse and noteworthy. Different geochemical classes identified by X-ray diffraction were nitrates, oxides, phosphates, silicates, and sulfates. Weathered cave limestone contributes notably to the formation of these minerals or compounds. FTIR spectroscopic analysis helped to identify minerals such as quartz, clinochlore, vermiculite, illite, calcite, and biotite.

Cave Microbes as a Potential Source of Drugs Development in the Modern Era

“…Most reported caves are composed of limestone, gypsum, and dolomite rocks [ 27 ]. In addition to calcite, other interesting minerals reported in caves are aragonite, similar to calcium carbonate (CaCO 3 ), but not as common as CaCO 3 , and mainly found in intricate needles called anthodites [ 28 ]. Selenite was also reported in some caves in small concentrations [ 27 ].…”

“…Approximately 45% of known bioactive compounds are secreted by Actinobacteria, of which 85% are derived from the Streptomyces genus [ 48 ]. The occurrence of the Streptomyces genus was documented in many caves, including the Mungkorn Tong Cave in Thailand [ 49 ], Karst Cave in Turkey [ 50 ], Kashmir Cave in Pakistan [ 28 ], Kotumsar Cave in India [ 51 ], Miroc Mountain Cave in Serbia [ 52 ], Helmcken Falls Cave in Canada [ 53 , 54 ], a limestone cave in China [ 55 ], Bolshaya Cave in Russia [ 45 ], Azorean and Canadian volcanic caves [ 56 ], Chaabe Cave in Algeria [ 57 ], Iron Curtain Cave in Chilliwack, Canada [ 58 ], Parsik Cave in Turkey [ 59 ], and Scarisoara ice cave in Romania [ 60 ]. Other genera of Actinobacteria ( Arthrobacter , Nocardia , Saccharothrix , Lentzea , Micrococcus , Nonomuraea , Spirillospora , Micromonospora , Microbacterium , Cryobacterium , and Lysinibacter ) were also reported in various cave environments [56, 58, 62 − 66].…”

Biodegradation of polyethylene by bacterial strains isolated from Kashmir Cave, Buner, Pakistan

“…Atomic absorption spectroscopy was performed to determine the concentration of elements in the cave soil sample (ZADA et al, 2016 -1 in cave soil and 8.14 mg kg -1 in control soil were much lower than those found in the control soil (Zada et al, 2016).…”

“…Samples were collected from the dark end of the cave about 188 m from the entrance. This cave is located far away from human access, so human intervention is negligible (Zada et al, 2016). The samples were then brought to the laboratory in an icebox and stored at 4 8C for further processing.…”

“…Caves can either be terrestrial or aquatic. Some may be rich in specific natural minerals or have exposure to nutrient sources, and therefore, different caves will have different types of microorganisms inhabiting various ecological niches (Zada et al, 2016). Fauna, environmental factors, temperature, humidity, organic matter, and other environmental factors influence activities such as nutrient cycling, and geomicrobiological activities including the formation or alteration of cave structures (Adetutu and Ball, 2014).…”