Nepal Journal of Biotechnology最新文献

{"title":"Isolation of Polyhydroxybutyrate (PHB) Producing Bacteria, Optimization of Culture Conditions for PHB production, Extraction and Characterization of PHB","authors":"Christina Thapa, Pallavi Shakya, R. Shrestha, S. Pal, P. Manandhar","doi":"10.3126/NJB.V6I1.22339","DOIUrl":"https://doi.org/10.3126/NJB.V6I1.22339","url":null,"abstract":"Polyhydroxybutyrates (PHBs) are energy reserves synthesized by different micro-organisms such as Alcaligenes, Pseudomonas, Staphylococcus, Algae, in excess of carbon and limitation of nutrients like nitrogen. These biopolymers are suitable alternate to synthetic carbon-based polymers. However, the high production cost limits their commercialization. The aim of this study was thus, focused on optimization of culture condition for maximum PHB production in an attempt to reduce the production cost. The micro-organisms for this purpose were isolated from 4 different soil samples and screened for PHB production. Culture conditions for these organisms were optimized by changing the parameters, viz., incubation time, pH, carbon source and NaCl concentration. Thus, optimized culture condition was used to culture the isolates for extraction of PHB and its analysis. The extracted compounds on FTIR-analysis gave characteristic C=O peak of PHB, thus, confirming the seven isolates to be PHB producers. Results for optimized parameters for the isolated PHB positive species showed that synthesis of PHB was maximum at 48 hours i.e. during the early stages of stationary phase. However, different isolates favored different culture conditions. Highest PHB accumulation and growth of isolates were seen at pH 7 and 9. Similarly, it was observed that glucose was favored by 4 isolates and sucrose was favored by 3 isolates. Interestingly, NaCl concentration did not cause significant effect on neither the bacterial growth nor the PHB production. During the extraction of PHB from the optimized culture conditions, extraction of PHB from broth gave significant yield than that from agar. A good PHB yield from broth amounting to 36.41% and 34.59% was observed for Bacillus pasteurii and Micrococcus luteus respectively, showing a potential for their exploitation in industrial PHB production. At optimized conditions, 7 isolates exhibited significant PHB yields, thus showing a potential for further exploitation.","PeriodicalId":34186,"journal":{"name":"Nepal Journal of Biotechnology","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78276730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclospora cayetanensis: An Infestation among Diarrheal Children in Kathmandu Valley, Nepal","authors":"B. Bhattachan, G. Rai, Nabin Narayan Munankarmi, J. Sherchand","doi":"10.3126/NJB.V6I1.22332","DOIUrl":"https://doi.org/10.3126/NJB.V6I1.22332","url":null,"abstract":"Cyclospora cayetanensis, a coccidian parasites which is responsible for recurring diarrhea and gastroenteritis especially among children living under poor hygienic condition in developing country like Nepal. Aimed of this research is to find out the prevalence of intestinal parasites and C. cayetanensis among diarrheal children in a Pediatric Hospital in Kathmandu valley, Nepal. Cross-sectional type of study was done. Altogether 196 stool specimens were collected from June to September 2013 among outpatient diarrheal children in Kanti Children’s Hospital. Modified Ziehl Neelson staining method was applied for detection of oocysts of Cyclospora after formal-ether sedimentation. Parasites were detected in 13.7% (27/196) of stool samples from ≤ 15 year old diarrheal patients. C. cayetanensis was detected in 4.8% (8/196). In genderwise, infection rate of C. cayetanensis 4.5 % (5/112), in male were higher than 3.6% (3/84) in female. In agewise, infection rate of C. cayetanensis in 5.7 % (3/52) 11-15 year old were highest followed by 4.1% (3/78) in 0-5 year old and 3.0% (2/66) in 6-10 year old. In seasonwise, infection rate of Cyclospora was highest in the month of August 7.4% (4/54) followed by 3.9% (2/51) in July, 2.3% (1/44) September and 2.1% (1/47) in June. Altogether five different type of parasites were detected. Infection rate of Giardia lamblia were highest 5.1 % (10/196) whereas lowest was Cryptosporidium parvum 1.0 % (2/196). Prevalence of C. cayetanensis is highly probable to infant, neonate, toddler and diarrheal children. Therefore, attention should be made in laboratory investigation of C. cayetanensis while suspecting the diarrheal patients infected with other parasites.","PeriodicalId":34186,"journal":{"name":"Nepal Journal of Biotechnology","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84197626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technologies for the Extraction, Separation and Purification of polyphenols – A Review","authors":"Shyam Suwal, A. Marciniak","doi":"10.3126/NJB.V6I1.22341","DOIUrl":"https://doi.org/10.3126/NJB.V6I1.22341","url":null,"abstract":"Polyphenols are high molecular weight, organic molecules mainly found in plant kingdom. They are mostly known for their positive impact on health, specifically for their antioxidant activity. Indeed, they are widely studied for the prevention of multiple diseases such as cancer, inflammatory, cardiovascular and neurodegenerative diseases. Nevertheless, extractions of these growing interest molecules remain challenging using conventional methods such as solvent extraction. That is why recent researches have focused on improving the extraction of polyphenol by using different technologies such as ultrasound, microwave, pressurized liquid, pulsed electric field, supercritical fluid and high hydrostatic pressure. In the current context, the assisted-extraction should demonstrate their potential to improve the extraction efficiency while being cost-effective and with a low environmental impact. To this end, technologies ought to, for instance, increase the solubility of polyphenol and the permeability of the cell wall. Consequently, this review is focused on the use and potential of these technologies to improve polyphenol extractions from plants as well as their purification using various methods. It discusses of the advantages and disadvantages with some examples of all these technologies assisted-extraction in comparison with conventional extraction method as well as purification technology.","PeriodicalId":34186,"journal":{"name":"Nepal Journal of Biotechnology","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88590002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nipah Virus (NiV) Infection: Is Nepal Prepared for the Possible Outbreak?","authors":"Dhiraj Shrestha, B. Bhattachan","doi":"10.3126/NJB.V6I1.22340","DOIUrl":"https://doi.org/10.3126/NJB.V6I1.22340","url":null,"abstract":" After 20 years of the first Nipah Virus (NiV) outbreak in the world, it re-emerged as the outbreak in India. WHO has recognized NiV as a potent epidemic threat to human health. Both animal-to-human and human-to-human transmission of zoonotic NiV has been documented. Fruit bat of Pteropodidae family is the natural reservoir of the virus. Thus, the territorial habitat of these bats is the high risk zone of NiV outbreak. The symptoms are very nonspecific and the pathogenicity of NiV is yet to be fully understood. Diagnosis of NiV infection still relies on molecular techniques. Till date, no drugs or vaccines against NiV has been approved. Some research have presented arrays of the possible treatment and prevention option, but without sure shot implications. So, appropriate precautions are the only currently available prevention option. Nepal is yet to experience a NiV outbreak but that does not undermine the risk posed to the general population. High risk countries including Nepal should be well prepared to tackle the possible outbreak in future.","PeriodicalId":34186,"journal":{"name":"Nepal Journal of Biotechnology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89487561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}