Search or add a thesis

Advanced Search (Beta)
Home > Microbial Strain Development for Hyperproduction of Β–Glucosidase Through Γ–Rays Mutagenesis and Expression Cloning

Microbial Strain Development for Hyperproduction of Β–Glucosidase Through Γ–Rays Mutagenesis and Expression Cloning

Thesis Info

Access Option

External Link

Author

Javed, Muhammad Rizwan

Supervisor

Muhammad Hamid Rashid

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2013

Thesis Completion Status

Completed

Subject

Natural Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1064

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726639764

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


The cellulose enzymatic hydrolysis is carried out by the synergistic action of cellulase enzyme complex, namely endo-glucanase, exo-glucanase and β-glucosidase (BGL). BGL is responsible for the regulation of the cellulolytic process as both endo- and exo-glucanase activities are often inhibited by cellobiose. In recent years, interest in BGL has gained momentum, owing to its potential use in various biotechnological processes including biomass degradation, fuel ethanol production, release of aromatic residues, extraction of fruit juices, production of fermented foods etc. A. niger is by far the most efficient BGL producer among the microorganisms investigated. To cope with the current industrial demand it is necessary to produce BGL with improved catalytic and kinetic properties. The current report deals with the development of A. niger strain through gamma rays treatment. Hyper producer mutant M-6 was selected on the basis of 2-deoxy-D-glucose resistance, which showed about two fold higher production of BGL as compared to control. Both the parent and mutant had shown best results with 3% wheat bran at 30 °C and pH 5. Random mutagenesis resulted in mutations within the BGL gene sequence, leading to overall conformational change in BGL secondary structure. The subunit and native molecular mass of the BGLs from parent and mutant were same i.e. 130 and 252 kDa, respectively. LC-MS/MS analysis also confirmed the identity of protein bands as BGL from both strains with a slight difference in molecular masses. The mutant BGL proved to be 1.6 fold efficient for cellobiose hydrolysis with lower activation energy (Ea) and thermodynamically more stable against denaturants than parent BGL. The mutant BGL gene was also expressed in Pichia pastoris and the recombinant BGL possessed similar characteristics as that of the mutant BGL. Effect of metals on parent and mutant BGLs showed that Ca2+ decreased the Ea, resulting in efficient formation of ES*-complex as compared to apo-BGL, while, Mn2+ decreased the Ea at lower metal concentrations only. The heat of ionization for the acidic and basic limbs of the apo- BGL reduced significantly in the presence of Ca2+ and Mn2+. The turnover (kcat) of apo-BGL showed an increase in the presence of low concentrations of Ca2+ and Mn2+. The BGL activation mechanism by Ca2+ was of mixed nature where Ca2+ was preferably binding with free enzyme, while Mn2+ was preferably binding with ES*-complex rather than free enzyme (partially un- competitive). Ca2+- and Mn2+- bound BGL also showed higher thermo-stability as compared to apo-BGL. Immobilization of BGL through entrapment on latex and silicone resulted in an increase in optimum temperature and thermal stability than the free enzyme. The immobilized BGL also increased the cellulose hydrolysis rate with more than 70% functional stability after multiple reuses. The current study has resulted in a highly stable and catalytically active BGL enzyme which may have substantial applications in biofuel and biorefinery industries.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

مولاناسید احمد ہاشمی

مولانا سید احمد ہاشمی
افسوس ہے کہ گزشتہ مہینے ممتاز عالم دین اور سر کردہ ملی و قومی رہنما مولانا سید احمد ہاشمی سابق ممبر پارلیمنٹ نے داعی اجل کو لبیک کہا۔ وہ عرصے سے موذی امراض میں مبتلا تھے۔ ۴؍ نومبر ۲۰۰۱؁ء کو ان پر دل کا شدید دورہ پڑا اور اسپتال جاتے ہوئے مالکِ حقیقی سے جاملے، اناﷲ وانا الیہ راجعون۔
مولانا غازی پور کے ایک شریف خانوادے سے تعلق رکھتے تھے، ان کے والد حافظ محمد شفیع صاحب نے دارلعلوم ندوۃ العلما لکھنؤ میں اس زمانے میں تعلیم پائی تھی جب وہاں مولانا سید سلیمان ندوی بھی زیر تعلیم تھے اس لیے دونوں کے اچھے روابط تھے، مولانا ہاشمی بچپن ہی میں والدین کے سایہ شفقت سے محروم ہوگئے ان کی پرورش ان کے بڑے بھائی حافظ سید محمد ہاشمی نے کی، نانہال دربھنگھ سے غازی پور لاکر یہاں کی مشہور دینی درس گاہ مدرسہ دینیہ میں ان کا داخلہ کرایا، عربی کی پانچویں جماعت تک تعلیم دلانے کے بعد انہیں کلکتہ لے گئے اور مدرسۂ عالیہ میں داخلہ کرایا جہاں سے ’’ممتاز المحدثین‘‘ کی ڈگری لی پھر دارلعلوم دیوبند میں مولانا سید حسین احمد مدنی سے دورہ حدیث کی تکمیل کی۔ دارلعلوم سے فراغت کے بعد چند دن دہلی میں رہے اور پنجاب یونیورسٹی کے امتحانات دئیے، اسی زمانے میں مولانا محمد حفظ الرحمان سیوہاروی ناظم جمعیۃ علمائے ہند کی صحبت اور قربت نصیب ہوئی۔
دہلی میں مختصر قیام کے بعد وہ کلکتہ واپس آگئے، ان کے بڑے بھائی چاہتے تھے کہ اب وہ کوئی کاروبار کریں لیکن اس وقت تو وہ بورڈ کے مدرسہ ’’ندائے اسلام‘‘ میں مدرس مقرر ہوئے مگر شروع سے دین و ملت اور قوم و وطن کی خدمت کی جانب ان کی طبیعت کا رجحان تھا اس لیے اسی مشغلے میں ان کی زندگی گزری۔
کچھ عرصہ صحافت...

Social Framework Analysis Through Oedipus Complex in Lawrence’s Sons and Lovers

Sons and Lovers has always been posing problems for the teachers, during classroom critical discussions on the novel on account of its undue association with Freud’s concept of Oedipus complex and his focus on sexual instincts. Readers are forcibly led to the conclusion that there is convincing evidence of unconscious sexual attraction between Gertrude (the mother) and William and Paul (her sons) throughout the novel. The novel basically focuses on the individual’s mental and behavioral struggle to locate his own place in the social setup in pursuit of his dignity. An open-minded close examination of the novel makes one realize that it hardly deserves to be labelled as an illustration of Freud’s theory of Oedipus complex. Paul’s struggle for recognition and acceptance in the society is the central theme of the novel, which puts him in trying conditions and relations and leaves him struggling to adjust his place in quest of self-esteem and recognition. The more he tries to get satisfaction, the more he becomes disillusioned. Consequently, dissatisfaction leads him to interact with different people and he experiences maladjustment. The object of this paper is to analyze Paul’s relations with other main characters in the novel in order to diagnose the cause of his discontentment in his relations with them. An attempt has been made to view his predicament in the light of psychological and social cross-currents that pervade his behavior through-out the novel, Paul finds intellectual harmony with Miriam as her feelings match with those of his. Like Paul, she also wants to achieve something great. A cleavage occurs in their relationship when Miriam shows her reluctance to fulfil his carnal desires, as being unethical and contrary to her spiritual ideals. Paul’s sensual desires are fulfilled by Clara, a woman promising physical satisfaction but devoid of aesthetic sensibilities, which again compel him to turn to some new destinations. A thorough analysis of the novel Sons and Lovers clearly reveals that there is very little influence of Oedipus complex, while there is a strong chemical bond and natural affection between the mother and son which is a natural human instinct. Paul finds solace in the company of Gertrude simply on account of natural reasons and not for any amoral urge like Oedipus complex.

Influence of Social Class on Cognitive Development of Syntax: A Study of Pakistani Efl Learners

Language has long been considered a cognitive phenomenon by theorists who believed that it is in cognition that language develops as a communication tool. However, cognitive linguistics recently realized that language is not merely an innate, natural or cognitive phenomenon, but develops in socially and culturally situated cognition. Cognitive sociolinguistics emerged as a sub-discipline of cognitive linguistics which believed that selection of linguistic variants by its users is governed not only by cognitive but also social constraints. Social constructionism as an approach became relevant to this conception of language as it guided the researchers to believe that cognition and language are socially constructed phenomena. Social cognition theories explained the link between cognition and society, and made it easy to understand language as a social cognitive phenomenon rather than a purely cognitive one. Variationist studies focused on the link between linguistic and social variables, and researchers started to study the link between linguistic variants and social classes of the speakers. In the same vein, this research project aims to explore correlation between social class and the cognitive development of syntax among the learners of English language in Pakistani universities. It aims to highlight how social approaches to language differ from cognitive approaches in their understanding of language acquisition and how the former emphasizes the social nature of language development. The study follows correlational method of research to find out the relationship between social class of the adult learners of English and cognitive development of syntax among them. Apart from social class, which is the main social variable studied in this research for its correlation with cognitive development of language, the research also takes into account gender, marital status and age as extraneous variables and studies the relationship of these with the sample’s performance in a syntax-based test. The population for this study consisted of male and female students of English language courses belonging to three universities of Pakistani capital Islamabad. To collect social class data and test syntactic skills of the sample, two research tools were designed; a Socio-economic Index (SES Index or SEI) and a Syntax-based test. The SES Index consisted of five social class variables. These are occupation, income, educational qualification, medium of instruction, and property. The sample was asked to provide details of the said variables about three family members; the subjects themselves, their fathers and mothers. The second tool designed for this research was Syntax test which aimed to test various syntactic skills of the sample. Their performance in the syntax based test was considered an indicator of their cognitive development. The participants were required to fill up the SES Index and solve the test. Both the tools had equal marks, that is, 100. This class score of the respondents was studied for its correlation with the syntax score. SPSS was used to study correlation between social class score / SES score of the individuals and their syntax score. The results yielded moderately significant positive correlation between social class of the individuals and their syntax score and the hypothesis that there is a positive correlation between the two variables was retained. Further, the population was divided into three social classes on the basis on 33% percentile and regression was run to see mean score difference, which pointed out significant mean difference in three SC groups. T-test and Mann Whitney were run in SPSS to study the relationship between gender, marital status and age and syntax. The data were categorized according to these variables and then the tests were applied. In case of gender, which is the first extraneous variable, the mean difference between males and females was significant with females scoring more in syntax test than males, but SPSS showed that these results were statistically non-significant, so the hypothesis of unequal variance between males and females was rejected. The t-test regarding married and single population proved statistically significant difference with married scoring higher than the singles in syntax test. Unlike gender and marital status variables, age variable had three groups, and due to non-homogenous population in these three groups, non-parametric Mann-Whitney test was run. No statistically significant difference was found in the mean rank of age group 1 and 2, and 1 & 3. Also, no statistically significant difference was found in the mean rank of the two age groups, which proved equal performance in syntax test by both groups.