Pestalotiopsis microspora is an endophytic producer of bioactive compounds of therapeutic importance. Despite its therapeutic and industrial applications, its safety profile in animals including humans remains elusive. This study investigated the nature of acute and repeated dosing toxicity of P. microspora filtrate (PMF) on the hematological parameters and vital metabolic organs in vivo. For the acute testing, the animals were administered a single oral dose (2 ml/kg b.w.) of PMF and observed for 14 days for probable signs of toxicity. Repeated dosing was carried out by once daily oral gavaging with graded doses (0.25, 0.5, and 0.75 ml/kg b.w.) of PMF for 28 days. Throughout the two experimental periods, no deleterious behavioral changes and clinical signs of toxicity were observed. However, except for the significant differences (p < 0.05) in the body weight, platelet, and white blood cell counts of the PMF-treated animals relative to the control, data obtained on the hematological parameters of the PMF-administered rats compared favorably with those of the control group in the 28-day toxicity assay. This observation suggests parameters-specific toxicity and was supported by the PMF-induced necrosis and cytoarchitectural distortions in the organs of the animals. Study to confirm the presence of toxins/antinutritional factors in PMF to better understand its toxicological dynamics is imperative.

Fungi are important decomposers in our ecosystem and are useful in metabolite production, bio-degradation and bio-sorption of different substrates and wastes through their mycelial biomass. Fungal species are known to have different preferences for their growth requirements. Two fungal species Pestalotiopsis and Pseudopestalotiopsis useful in many biotechnological applications were studied. Nutrient and physiological requirements for mycelial biomass production such as carbon and nitrogen, pH, light and temperature were investigated. Both fungal isolates were grown in liquid basal medium supplemented separately with various carbon and nitrogen source and incubated under different light, pH and temperature conditions for 15 days. In general, Pestalotiopsis sp. and Pseudopestalotiopsis sp. showed significant preferences for monosaccharide and disaccharide carbon source as compared to sugar alcohols and polysaccharides, whereas ammonium tartrate was more preferred as a nitrogen source compared to ammonium nitrate, ammonium sulphate and other ammonium salts. These two fungal species were able to grow and produce good mycelial biomass (223.33 mg for Pseudopestalotiopsis and 136.67 mg for Pestalotiopsis) at temperature range of 15°C to 30°C and (290.00 mg for Pseudopestalotiopsis and 256.67 mg for Pestalotiopsis) on media pH of slightly acidic to slightly alkaline. However, they showed no significant preferences between constant light, total darkness and alternate light conditions. The results from this study will be very useful for the mycelial biomass production of Pestalotiopsis sp. and Pseudopestalotiopsis sp. for their biotechnological applications.