Paras N. Singh

Phosphate solubilizing ability of two Arctic Aspergillus niger strains

Many filamentous fungi were isolated from the soils of Ny-Ålesund, Spitsbergen, Svalbard, and were screened in vitro for their phosphate solubilizing ability. Two strains of Aspergillus niger showed good tricalcium phosphate (TCP) solubilizing ability in Pikovskayas medium. The TCP solubilization index was calculated at varying levels of pH and temperatures. The ability of Aspergillus niger strain-1 to solubilize and release inorganic-P was 285 µg ml–1, while Aspergillus niger strain-2 solubilized 262 µg ml–1 from 0.5% TCP after seven days. This is the first report of TCP solubilization by Arctic strains that may serve as very good phosphate solubilizers in the form of biofertilizer.

Pigment, fatty acid and extracellular enzyme analysis of a fungal strain Thelebolus microsporus from Larsemann Hills, Antarctica

A cold-tolerant fungal strain Thelebolus microsporus was investigated for the first time for its pigment and fatty acid production. High-performance liquid chromatography analysis confirmed the presence of carotenoid pigment. Gas chromatography observations showed the presence of major fatty acids: myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0), heptadecanoic acid (17:0), linolenic acid (18:3) and linoleic acid (18:2). Of these, linolenic acid, a polyunsaturated fatty acid, was present in substantial quantity, suggesting that it may have a role in adapting the fungus to low Antarctic temperatures by modulating membrane fluidity. The commercial application of linolenic acid is as a food supplement for humans suffering from eczema, cardiovascular disease and diabetic neuropathy. Another fatty acid, linoleic acid, a precursor of 1-octen-3-ol, is the principal aromatic compound in most fungi and has also been documented in this strain. Screening of the fungal culture for extracellular enzyme activity for amylase, protease, lipase, chitinase and cellulase was carried out. The isolate showed maximum α-amylase activity at 20°C, suggesting effective applications as a detergent additive, in textile processing and in the food industry.

New species of Pseudocercospora causing leaf spots of forest plants of Nepal

Descriptions and illustrations are provided for three new species of Pseudocercospora, P. justiciicola sp. nov. on living leaves of Justicia simplex, P. hibiscigena sp. nov. on Hibiscus sp. and P. pileae sp. nov. on Pilea umbrosa from Nepal. They are compared and contrasted with similar species.