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Environment Friendly Leather Making and Recovery of Value Added Products from Solid Tannery Waste

Thesis Info

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Author

Siddique, Aisha

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Microbiology

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11441/1/Aisha%20Siddique%20microbiology%202019.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726068903

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Leather industries contribute substantially to the environmental pollution due to huge quantum of solid and liquid waste generated. It is a chemical processing industry facing major environmental challenges, with most crucial one of waste minimization. Chemicals used in leather processing steps i.e., tanning are mostly health hazardous posing serious threats to ecosystem. Research is under way to develop alternative low cost, low waste, cleaner process technologies by reducing the pollution and chemical load on the environment. Intensive efforts are being directed towards use of enzymes as plausible alternative technology for soaking, dehairing and bating processes. Use of cheaper, less toxic and biodegradable proteases for dehairing may reduce or completely eliminate the use of sodium sulfide producing equally fine quality leather. Therefore, the aim of this current research work was to produce bacterial proteases that can be used for dehairing goat skin and hides as an alternative environment friendly process that may replace conventional method of using sodium sulfide in larger amounts. In the present study, thirteen indigenous bacterial strains were isolated from soil samples of Pakistan and screened for their proteolytic potential by measuring zone sizes of protein hydrolysis on nutrient agar plates with 1% casein as substrate. Bacterial strains RM1and ASM1 produced largest zone sizes of hydrolysis of 29mm and 22mm respectively on 1% casein agar plates after flooding with 10% TCA in qualitative protease assay and were selected for further studies. Based on morphological, biochemical and 16S rRNA gene analysis these two strains ASM1 and RM1 were taxonomically characterized as Bacillus cereus and Bacillus subtilis with the nucleotide sequences submitted in NCBI database under accession number KJ600795 and KT004404 respectively. Both strains were cultured in shake flasks and different nutritional and cultural parameters were optimized by one factor at a time strategy in the batch experiments for maximum protease activity. Five different media with different protease substrates were assayed for higher enzyme production. Bacillus cereus ASM1 grows best in M4 medium with beef extract as protein substrate with 8.7 U/mg specific activity. The alkaline pH value of 9 was suitable for maximum protease activity along with 1% glucose as C-Source, inoculum size 2% (v/v ratio) at mesophilic temperature range (30-37⁰C). Maximum enzyme production with a specific activity of 9.58 U/mg was observed after 48 hours of incubation at optimized conditions for ASM1. For Bacillus subtilis RM1, maximum proteases production with a specific activity of 9.82 U/mg was achieved in M3 medium with malt extract as main carbon and nitrogen source. Other optimized conditions include 1% dextrose as best C-Source in 1% inoculum size at pH 6-7 after 48h incubation. Crude enzyme from both of the strains produced at optimized conditions of enzyme production was used in dehairing application of goat skin. Results for dehairing suggested that RM1 was having better efficacy than ASM1, showing complete removal of hairs after time of 24 h incubation. ASM1 can be used in degradation of trimmings and shavings from untanned hides but collagenolytic nature makes it unsuitable for dehairing. RM1 shows ability to produce thermo-tolerant proteases in bulk quantity by growing at high temperature up to 55oC as it was isolated from the soil bank of a hot water spring of Kashmir, Pakistan. Enzyme from Bacillus subtilis RM1 was purified by two step purification process after ammonium sulfate precipitation and gel filtration column chromatography. Overall yield of the enzyme was increased up to 7.53 folds with a specific activity of 55.125 U/mg (25%) after purification. Purified enzyme retained its catalytic activity over a broad range of temperature (5°C to 65°C) and pH (5-8). EDTA inhibited the efficiency of enzyme confirming it as a metallo-protease while SDS-PAGE analysis confirmed the size of protease as 28.24 kDa. Purified protease exhibited excellent stability and activity in the presence of polar solvents and detergents. Moreover, it retained significant enzymatic activity for higher concentrations of commercially available detergents suggesting that it could be used both in leather and textile industries with ecological benefits. Taking all together, it can be concluded that protease enzyme of Bacillus subtilis RM1 could be an attractive candidate for dehairing. Only about 20-25% of wet salted hides/skins are converted into commercial leather, while large percentage is lost in wasteland as leather shavings, buffing dust, trimmings and splits, fat, soluble proteins and solid suspended pollutants. The harmful effects of the traditional disposal methods for tannery wastes have created a dire need and demand for more cost effective and environmentally acceptable alternatives. The most ideal way to minimize the waste generated is to convert them in to reusable items. This has motivated the research community to search for more innovative uses and applications of tannery wastes. As the wastes are highly proteinaceous, a wide range of value added products can be retrieved making the leather industry as an integrated business with value creation opportunities. Present work also deals with the aim of developing an efficient and value-added process for the management of untanned trimmings, produced in large quantities during the pre-tanning operations. The objective is to extract collagen proteins from tannery waste, treat and to convert the isolated collagen into useful products. For this grounded limed, delimed-bated and alkali treated trimmings were dissolved to make a collagen solution using pepsin. The physico-chemical properties of the resultant sponges and effects of the processing steps on the sponges prepared from un-tanned hides were studied. Results showed that bating and alkaline treatments given to proteinaceous fiber networks after liming have considerable effects on the resultant properties of sponges. SDS-PAGE analysis showed the molecular weights of all three were maintained in the range as of a commercial Type 1 collagen i.e., 100-200kDa. Bating appears to be the best treatment among different treatments as it yields the sponges with best characteristics of water absorption and visco-elasticity. Also, it has positive effect on reducing the apparent density of sponges, within desirable density ranges. Thus, the preliminary results of this study suggest feasibility of using these biobased collagen sponges prepared from un-tanned hides as absorbants that can be commercially viable.
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خراجِ محبت

خراجِ محبت
(در صنعتِ توشیح)
ی
یورشِ کرب و بلا میں عزم کا کوہِ گراں
و
ورطۂ حیرت میں گم ہے علم و فن کا آسماں
ن
نازشِ اہلِ محبت، افتخارِ دوستاں
س
سرخوشی، وارفتگی کا ایک بحرِ بے کراں

ف
فصلِ گل میں ، حسن پرور ، گل رخوں کا ترجماں
ر
رشحہ فکر و نظر ہے کیف و مستی کا جہاں
ی
یاس نگری میں قسیمِ حوصلہ، ہمت نشاں
د
دشتِ نفرت کو قلم اس کا بنائے گلستاں
ی
یکہ تازِ فکر و فن ہے ، شاعرِ ندرت نشاں!
جمشید کمبوہ

اسلام میں عورت کے حق طلاق کی حیثیت ایک تحقیقی جائزہ

Of the several factors that justify the greatness of Islamic Culture and survived the test of time, one is the pride of place ascribed to woman in human society. Since the dawn of Islamic civilization, woman has been respected and cored and her rights have been protected and, thus, womanfolk has been made a purposeful existence. However, Islam, being a religion of nature, does not bring woman on the line of equality with man as the Islam is the religion of justice; not that of equality. The Holy Quran has very apparently determined the rights and duties of man and woman and these all are based on natural facts and laws as well. In the contemporary times, progressive as well as west-inspired circles of our society have put numerous objections on the issue of divorce. They opine that by giving man right to divorce, woman has been deprived of equal status; hence this one-sided right has not only disturbed the family life, but put woman at an interior place. This point of view does not testify to the very facts of Islamic practices in connection with the institution of divorce. In order to understand the historical background of the institution of divorce, laws and practices in vogue in two major religions of the world-Judaism and Christianity, are discussed in a brief manner. Besides, various reforms, from time and again, introduced in divorce in west are also touched upon in nutshell. However, major portion of this article focuses on Islamic teachings regarding divorce and its implications. Therefore, this research article attempts to highlight the various aspects of divorce in the light of Islamicteachings in a comprehensive manner so as to remove the doubts of so-called west-oriented circles of our society.

A Physiologically Based Approach to Study the Toxicological Effects of Bisphenol S, an Endocrine Disruptor, on Reproductive System of Male Rats

Background: Bisphenols are widely used in manufacturing polycarbonate plastic, plastic toys and food containers. One of these bisphenols, bisphenol A (BPA) is the major component of baby bottles, dental sealants, epoxy resins and food packaging has been well documented for its hazardous and estrogenic mode of action. In many countries, BPA has been banned in some applications and has been replaced by bisphenol S (BPS). However, nearly similar estrogenic potential of BPS to BPA has been reported in different studies. It has been detected in food, receipt papers and in water. Humans are prone to its exposure through dermal exposure and dietary food intake. An increase in the concentrations of BPS has been detected from 2010 to 2014 in human body fluids, suggesting the possibility of increased exposure to BPS in daily life. BPS has shown estrogenic mode of action, oxidative stress inducing potential, obesogenic effect as well as anti-androgenic effects in vitro. In the in vivo studies, BPS exhibited antiandrogenic effect in male zebra fish, decreased gonadosomatic index in female fish and affected endocrine functions. Similarly, BPS concentrations have been linked to the oxidative stress in the humans, however, in mammalian reproductive system; data regarding BPS toxicity is limited. In present studies, we first assessed in vitro effect of BPS on testicular tissues and sperm. Secondly, we aimed to evaluate whether sub-chronic and chronic exposure of BPS can modulate reproductive functions of male rats in vivo. Lastly, the potential effect of BPS on gonadal development of male rats exposed during pre-natal and neonatal periods were evaluated. Materials and methods: Stock solution of BPS was prepared by dissolving 0.5 g in 5 mL of ethanol and was further diluted with media/water to the final concentration of less than 0.5% ethanol in the media/water. In order to attain the first goal, testicular tissues and sperm from adult rats were incubated with media alone or in combination with different concentrations (0.5, 1, 10 and 100 μg/L) of BPS for two hours in 5% CO2 and 95% air at 37 0C. Testicular testosterone concentration was determined through Enzyme Linked Immuno Sorbant assay (ELISA), while testicular tissue and sperm oxidative stress was determined through estimation of antioxidant enzymes activity, lipid peroxidation (LPO) and generation of reactive oxygen species. To achieve the second goal, adult male rats were treated with different concentrations (1 - 50 μg/kg/day) of BPS through oral gavage for 28 days. Secondly, male rats (22 days old) were provided with water containing different concentrations of BPS (0.5, 5 and 50 μg/L) for a period of 48 weeks in water. Animals were killed by cervical dislocation; blood was collected 27 and was used for determination of different hormones in the plasma while testicular and epididymis tissues were used for histology, oxidative stress determination and evaluation of different parameters of sperm. In the next set of experiments, effect of BPS on the development of male gonads was assessed by exposing the animals to different concentrations of BPS during pre-natal and neonatal period of development. In the pre-natal exposure study, pregnant female rats were provided with water containing 0 and 0.5 - 50 μg/L of BPS. The pups born were assessed for alteration in the early sexual development and reproductive functions during adult hood. In the neonatal exposure study, male pups were subcutaneously injected with different concentrations of BPS (0.5 - 50 mg/kg.day in 50 μL castor oil) from post-natal day 1 to 10 and were followed in the adulthood for alterations in the reproductive functions. Plasma hormones levels, histological changes and alteration in the sperm parameters were determined and compared with the control. Results: In the in vitro exposure study, oxidative stress in the testis and sperm was enhanced along with the increase in antioxidant enzymes activity. At the highest concentration, BPS induced formation of reactive oxygen species, caused lipid peroxidation, affected superoxide dismutase levels, and increased DNA fragmentation in the rat spermatozoa. Similarly, BPS induced reduction in the testosterone secretion by the testis at highest concentrations tested. On the other hand, in the in vivo sub-chronic and chronic exposure study, testicular reactive oxygen species (ROS) and lipid peroxidation (LPO) were significant increase in the higher doses tested while antioxidant enzymes activity were significantly reduced. Sub-chronic exposure for 28 days reduced plasma and intra-testicular testosterone, plasma luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations were suppressed in the groups treated with higher doses of BPS. Testicular morphology revealed thin seminiferous epithelium in the treated groups than control. In the epididymis, area of the tubular epithelium showed significant reduction and empty lumen were observed in the groups treated with higher concentrations of BPS. Chronic exposure of male rats to different concentrations of BPS showed a significant alteration in the gonadosomatic index (GSI) and relative reproductive organs weights. Oxidative stress in the testis was significantly elevated while sperm motility, daily sperm production (DSP) and number of sperm in epididymis were reduced. Plasma testosterone, LH and FSH concentrations were reduced and estradiol levels were high in 50 μg/L exposed groups. Histological observations included significant reduction in the epithelial height of the testis along with disrupted spermatogenesis. Other prominent observations were empty lumen of the seminiferous tubules and caput region of the epididymis. 28 Pre-natal exposure to different concentrations of BPS induced no significant alteration in early sexual development as well as in adulthood of male rats. Body weight gain, Ano-genital distance (AGD), nipple retention (NR) and organs weight exhibited no change. However, exposure to different concentrations of BPS in the neonatal stage resulted significant decrease in GSI and relative organs weights in BPS 5 and BPS 50 mg/kg.day treated groups as compared to the control. Slight delay in puberty onset in the highest dose treated group was noted but this delay was not different than control. Hormonal analysis showed a significant reduction in testosterone and significant elevated levels of estradiol was observed in the treated groups compared to the control. Histological alterations included reduction in epithelial height and diameter of the seminiferous tubules and spermatids arrest. Reduction in the DSP and sperm number in the caput was observed in the highest dose treated group than control. Conclusion: In conclusion, BPS can not only induce oxidative stress in the sperm and testis in vitro but can also exert its toxicological and endocrine disrupting potential in vivo. Beside its effect in adult animals, exposure to higher concentrations to BPS during neonatal stage of development imparts adverse alterations in the reproductive tissues of male rats. BPS exposure exert its effects by inhibiting cell defense system, inducing ROS and LPO which results in adverse structural and functional changes in the reproductive system. These changes are more prominent and long lasting when the animals are exposed in early stages of life especially during the neonatal stage of development. These affects seems to be accompanied by gonadotropin suppression, estrogenic and antiandrogenic effects of BPS, which ends up with the deleterious alterations in the testis of rats that can lead into infertility.