International Journal of Applied Sciences and Biotechnology

140-148

Authors: Bibek Rana Chhetri, Dipika Acharya, Arjun Gautam, Nasala Bajracharya, Anuj Shrestha, Smriti Khadka

Lignocellulosic biomasses (LCB), second-generation biofuels are used as an alternative means to cope with the burning issues of depleting fossil fuels like petroleum products with the added advantage of renewability, lower emission, and lesser pollution. For the increment in the production of LCB biofuels, microbial pre-treatment processes are conducted which accelerates the degradation of organic polymers like lignin and hemicellulose with the activity of potential microorganisms. To increase the efficiency of degradation of hemicellulose, hemicellulolytic fungi including Trichoderma and Aspergillus and other bacteria produce multi-enzymatic complexes like cellulosomes. Similarly, organisms like Tinea versicolor, Dichomitus squalens, Phlebia floridensis, Daedalea flavida, and Phlebia radiata contain lignin-degrading auxiliary enzymes and lignin modifying enzymes like laccase and heme-containing peroxidase which aid in delignification process. Several factors are associated with pre-treatment processes like the type of strain, inoculum load, pH, temperature, fatty acids, C/N ratio, time, aeration, grindability, surface area, particle size, and supplements added. To enhance the pretreatment method, the combination of microbial with physical, chemical, and mechanical methods is suggested which leads to a synergistic effect and better yield of the final product. Overall, biofuels should be more employed and this review aims to bring light to the microbial pre-treatment approaches which can aid in the efficient production of biofuels that can directly contribute to environmental

164-170

Authors: Narayan Kunwar, Manoj KC, Rashika Shrestha, Sushil Chaudhary, Anima Shrestha, Bibek Rana Chhetri

With rapid population growth, unmanaged urbanization, and industrialization, the holy river Bagmati, has become one of the most contaminated water sources in Kathmandu, Nepal. As a result, the river has lost its capacity for self-purification and became ideal habitat for many pathogenic microorganisms such as E. coli, Salmonella, Vibrio, etc. The study aimed to perform the antibiogram profile of Salmonella species. According to the findings, Salmonella was identified in excessively polluted areas with sewage. Out of total 55 samples, 34.45% were Salmonella positive among which, 10.5% were found to be S. Typhi and S. Paratyphi, and the remaining 79% were found to be other S. enterica serovar. S. enterica serovar was detected in abundance from site B1. Site B2 yielded Salmonella Typhi and Salmonella Paratyphi isolates. Furthermore, Salmonella Paratyphi was isolated from Site B3. The water samples from Site B6 were proven to be Salmonella-free. Antibiotic Susceptibility Test was performed for the positive samples and all the serovars were found sensitive to Amikacin whereas least sensitive to Ampicillin i.e., 86.67%, 100%, and 50% resistant in case of other S. enterica serovar, S. Typhi and S. Paratyphi respectively. All the Salmonella species isolates were sensitive to Ciprofloxacin, Streptomycin, Ofloxacin, and Nitrofurantoin but 100 % resistant to Ampicillin. However, there is not a single data reported as Multi-Drug Resistant Salmonella species in this study. The study emphasized the use of effective treatments against the disease and addresses the health danger to people, animals, and many other living species living nearby the river.

182-189

Authors: Karun Adhikari, Ashis Rai

Blister blight is one of the most significant foliar fungal diseases of tea plant caused by Exobasidium vexans. An invitro experimentation on efficacy of biofungicides and chemical fungicides was carried out at Agriculture Research Station, Pakhribas from November 2020 to January 2021 to evaluate and analyze effectivity of two Trichoderma spp and five commonly used chemical fungicides against Blister Blight pathogen. Isolates of Trichoderma viride and Trichoderma harzianum were tested against E. vexans using dual culture technique. Five Chemical fungicides namely Copper oxychloride 50WP, Hexaconazole 5% EC, Metalaxyl 8% WP+ Mancozeb 64% WP, Carbendazim 50% WP, Carboxin 37.5% WS + Thiram 37.5% WS were tested at four different concentrations viz. 50 ppm, 100 ppm, 200 ppm and 500 ppm using poisoned food technique. The experiment was carried out in completely randomized design with three replications for each treatment. Both Trichoderma viride and Trichoderma harzianum demonstrated significant effect on mycelial growth reduction of E. vexans. Trichoderma viride and Trichoderma harzianum exhibited 70.87% and 66.98% inhibition in growth of E. vexans respectively. Similarly, Hexaconazole, Carbendazim, Carboxin + Thiram provided complete (100%) inhibition on pathogen growth regardless of concentration. Least inhibition (36%) on pathogen growth was recorded at 50 ppm of Copper Oxychloride. All chemical fungicides provided significant difference on reducing growth of pathogen in comparison to control at all concentration. It is recommended that Trichoderma spp be taken as a priority regarding its environmental benefit and furthermore if application of chemical fungicides is necessitated, rationalized use be done at lower dose and with appropriate timing.