Journal of Microbiology and Biotechnology

1-14

Authors: Muhsin Jamal

Biofilm is an association of micro-organisms in which microbial cells adhere to each other on a living or non-living surfaces within a self-produced matrix of extracellular polymeric substance. Bacterial biofilm is infectious in nature and can results in nosocomial infections. According to National Institutes of Health (NIH) about about 65% of all microbial infections, and 80% of all chronic infections are associated with biofilms. Biofilm formation is a multi-step process starting with attachment to a surface then formation of micro-colony that leads to the formation of three dimensional structure and finally ending with maturation followed by detachment. During biofilm formation many species of bacteria are able to communicate with one another through specific mechanism called quorum sensing. It is a system of stimulus to co-ordinate different gene expression. Bacterial biofilm is less accessible to antibiotics and human immune system and thus poses a big threat to public health because of its involvement in variety of infectious diseases. A greater understanding of bacterial biofilm is required for the development of novel, effective control strategies thus resulting improvement in patient management.

1-8

Authors: Baogui Xie

Fungal laccases always play important roles in various physiological and developmental processes. Here, we cloned a laccase gene, and named Vv-lac3, cDNA from the Volvariella volvacea, and expressed the cDNA in Pichia pastoris. The Vv-lac3 cDNA consisted of 1599 bp containing an open reading frame (ORF) encoding a 532 amino acids. The analysis of the deduced amino acids revealed that Vv-lac3 possessed a 19-amino acids signal peptide at the N-terminal end and a 513-amino acid mature protein. The Vv-lac3 contained four conserved copper-binding sites that which is the typical structure of fungal laccases. Phylogenetic analysis showed that Vv-lac3 had a high degree of identity with other basidiomycete laccases. Native-PAGE and SDS-PAGE analysis demonstrated that the product of Vvlac3 cDNA from P. pastoris was a functional laccase with a molecular mass of 65 kDa. The expression of the Vv-lac3 gene in V. volvacea increased during button stage to the elongation stage; it reached peaked in the elongation stage, and then decreased in the maturation stage, which suggests that this gene plays a regulatory role in stipe elongation in V. volvacea.

1-8

Authors: Ningxin Wang

The composition of a microbial community may be driven by geographic isolation, diet, and the phylogenies of host organisms. A null hypothesis was that the evolutionary history of microbial communities reflects the phylogenies of their respective hymenopteran hosts. The objective of this study was to test this hypothesis using four fig wasp species (Ceratosolen solmsi Mayr, Apocrypta bakeri Joseph, Philotrypesis pilosa Mayr, and Philotrypesis sp. Forster), which coexist in the spatially isolated fig cavities of Ficus hispida Linnaeus. The bacterial communities of the four fig wasps were investigated using culture-independent methods. The results show that these wasps harbored a total of 53 operational taxonomic units (3% distance cutoff for 16S rDNA sequences), and were dominated by Proteobacteria. Herbivore C. solmsi mainly harbored γ-proteobacteria (65.3%) and Actinobacteridae (23.9%). Potential omnivore P. pilosa was dominated by α- and γ-proteobacteria (80.5% and 4.9%). β-proteobacteria and Acidobacteria represented the majority of the bacterial communities of carnivores Philotrypesis sp. (51.2% and 16.8%) and A. bakeri (52.7% and 12.5%). Contrary to our hypothesis, the bacterial communities of the four fig wasps were clustered into three groups, which might be structured by both the diet and phylogenies of the host species. The fig-fig wasp system provides an isolated model for the extensive exploration of the ecological associations between insects and their microbes.

1-5

Authors: Hongmei Zhang

Biofilm formation is a significant hazard in food industry. This study aims to investigate the ability of sucrose esters to inhibit biofilm formation of food-borne Staphylococcus aureus. Twelve Staphylococcus aureus strains were isolated, identified and used for biofilm formation ability assay in presence or absence of sucrose esters. Bacteria adhesion the hydrocarbons test (BATH) was employed to analysis cell surface hydrophobicity rates of sucrose-ester treatments and correlation between biofilm formation ability and hydrophobicity. Various levels of biofilm formation inhibitory of sucrose esters were observed among all the isolates. Cell surface hydrophobicity (CSH) of all sucrose esters at concentrations of 3 mg/mL and 4 mg/ mL were reduced, suggesting a positive correlation between the biofilmproducing ability and the rates of CSH (P<0.05) as well as a significantly reduced CSH rates of sucrose esters during biofilm development (P<0.05). SE possesses great potential as an inhibitor for biofilm formation of foodborne pathogens.

1-4

Authors: Deyou Qiu

(E,E)-geranyllinalool (GL) can be used as an intermediate for chemical synthesis of several drugs as well as an insect pheromone and spice. Traditionally, (E)-nerolidol was used as a substrate to make (E,E)- geranyllinalool but the yield was low due to the multiple and complicated chemical synthesis processes. In this study, the (E,E)-geranyllinalool synthase gene (AtGES, At1g61120) from Arabidopsis thaliana was inserted into the Escherichia coli vector pET30a(+). E. coli strains containing plasmids pIRS and pGG that enable the synthesis of (E,E)-geranyllinalool precursors, when co-transformed with AtGES, were able to synthesize (E,E)- geranyllinalool with a yield up to 31.42 mg/L. This is the first report about the production of (E,E)-geranyllinalool by manipulation of multiple genes of its biosynthesis pathway in E. coli. Our results may facilitate metabolic engineering towards more cost-effective production of (E,E)-geranyllinalool in microorganisms.

1-5

Authors: Min Zhong

The emergence of multi-drug resistant-Mycobacterium tuberculosis (MDR-TB), especially the Rifampicin-dependent (R-) MDR-TB, has become a hot issue. To elucidate the potential mechanism that rifampicin-dependent MDR-TB (latent infection) utilizes for its long-term survival, we studied the morphology and L-form growth pattern of rifampicin-dependent MDR-TB. Rifampicin-dependent MDR-TB was isolated from fresh sputum of patients and showed favorable growth in the Rifampicin-containing conditions. Conversely, when R-MDR-TB was cultured in Rifampicin-depleted medium, bacterial growth ceased and MDR-TB transformed into L-form cells. This transformation process was studied over a span of three weeks by both optical microscope and transmission electron microscopy (TEM). At week one, the R-dependent bacteria cultured under rifampicin-null conditions exhibited acid-fast positive fried egg colonies and mycoplasma cell-like morphology. During week 2, the exhibited morphologies of the R-dependent MDR-TB were: acid-fast positive filamentous, granular sphere, cell membrane sugar-coat (filamentous particles aggregations) and protoplasms with various sizes and shapes. The morphologies of R-MDR-TB at week 3 were: tiny translucent colonies and giant sphere, filaments, protoplasm, fried egg colonies and "mycoplasma (filopodia)". These morphologies are typical and representative characteristics of L-form cells growth. These findings reveal the L-form growth of rifampicin-dependent MDR-TB for the first time, and elucidate the potential mechanism of rifampicin-dependent MDR-TB longterm survival (latent infection). This data will help to provide a foundation for novel early diagnosis and effective treatment of R- MDR-TB.

1-7

Authors: Yong Zhao

Vibrio parahemolyticus is an important pathogen that leads to food illness associated seafood. Therefore, rapid and reliable methods to detect and quantify the total viable V. parahaemolyticus in seafood are needed. In this assay, a RNA-based real-time reverse-transcriptase PCR (RT-qPCR) without an enrichment step has been developed for detection and quantification of the total viable V. parahaemolyticus in shrimp. RNA standards with the target segments were synthesized in vitro with T7 RNA polymerase and subsequently converted to cDNA for establishing the standard curve to quantify V. parahaemolyticus. The reaction efficiency was 94.56%, and was in the acceptable range. Without pre-enrichment, the sensitivity of RT-qPCR on quantifying V. parahaemolyticus in shrimp was 58 cfu/g, approximately. In addition, the survival of V. parahaemolyticus in spiked shrimp samples was quantified by RT-qPCR, DNA-based qPCR and standard plate count method. The quantification results of RT-qPCR have shown a good statistical correlation (R2=0.96) when compared to the standard plate count method. However, the correlation coefficient between plate count method and DNA-based qPCR was only 0.85 for quantifying V. parahaemolyticus. Based on the results, this new method could be an effective way for providing reliable quantitative data on viable V. parahaemolyticus in shrimp.

1-6

Authors: Yi Zeng

The presence of HPV DNA in cases of esophageal squamous-cell carcinoma has been reported repeatedly from Tangshan area of China and other regions with a high incidence of esophageal carcinoma. In current study, to investigate the presence of human papillomavirus in esophageal squamous cell carcinoma, 112 formalin fixed paraffin-embedded tissue samples of ESCC from Tangshan were evaluated for HPV16/18E6, HPV16/18E7, P16 and P21 proteins by Immunohistochemistry method. 112 samples divided to two HPV PCR positive and negative groups of 83 and 29 cases respectively. From 83 slides of PCR positive group 73(87.95%), 48(57.83%), 75(90.36%) and 72(86.74%) of slides had positive reaction for HPV16/18 E6, HPV16/18E7, P21 and P16 respectively. From 29 PCR negative cases 14(48.27%) and 15(51.72%) showed positive staining reaction for P16 and P21 respectively. Results showed a good direct relation between expression of two common cancerous proteins, P16 and P21, and HPV specific proteins by higher positive slides of 72/83 (86.74%) for P16 and 75/83 (90.36%) for P21 in group of positive HPV PCR, in compare with the lower positive result in negative HPV PCR group of 15/29 (51.72%) and 14/29 (48.27%) for P16 and P21 respectively. In this study, P16 and P21 were implicated as two good markers with high expression in ESCC cancerous tissue with HPV infection probability. Findings in this study raise the possibility that HPV is involved in esophageal carcinogenesis. Further investigation with a large sample size over different areas may be warranted.

1-8

Authors: Shan-Jing Yao

Mycelial pellets are microbial particles formed during fungi culturing and their formation mechanisms are still under investigation. Spore aggregation is often considered as a crucial step for fungi to form mycelial pellets. In this work, the pellet formation processes of three fungi were investigated for proving the mycelial pellet formation without spores, and a marine-derived Aspergillus niger was selected as an example for the mechanism studies of mycelial pellet formation, and detailed processes of mycelium agglomeration and pellet formation were recorded. Experimental results showed that mycelial pellets can be formed directly from hyphae and the spore aggregation may not be an essential step. Moreover, the culture media pH had substantial effects on the pellet formation processes. Scanning electron microscope and infrared spectroscopy results indicated that the decrease of pelletization capacity was related to the change of extracellular polymeric substances. However, mycelium could not grow into mycelial pellets after adding 100 g/L talc into the culture media, while the spore inoculation method could still result in the formation of mycelial pellets under the same condition. This result indicated that although spore aggregation may not be essential, it is likely an enhancing factor for the mycelial pellet formation.

1-11

Authors: Priya Bansal

Stem Cells are precursor cells that can give rise to multiple tissue types. The benefits to individuals and to society gained by the introduction of new drugs or medical technologies are difficult to estimate. The introduction of antibiotics and immunizations (vaccines), for instance, have significantly expanded life compasses and enhanced the wellbeing of individuals everywhere throughout the world. In spite of these different advances in the counteractive action and treatment of human diseases, devasting illnesses, for example, coronary disease, diabetes, tumor, and different neural diseases, for example, Alzheimer's disease present proceeding with difficulties to the wellbeing and prosperity of individuals all around. The science prompting the advancement of system and techniques for culturing human stem cells could prompt exceptional medicines and even cures for these and different diseases.

1-10

Authors: Praveen B

The usage of citric acid and vinegar from the past histories is used in food, pharma industry, and research and in different areas. Production of citric acid and vinegar using yeast is a very simple technique, but the production into large amounts of product with less expensive can be possible with the microorganism yeast. The initial process was carried out at the laboratory scale, to test whether the normal yeast or irradiated yeast can produce the high yield of citric acid and vinegar. Firstly, the baker’s yeast normal yeast- not irradiated was taken and used as an inoculum in the sources grapes and barley seeds into 3 different flasks simultaneously for both grapes and barley. The flasks with grapes and barley separately were fermented for 3, 6 and 9 days. After the fermentation for 3 days the fermented source of grapes and barley were distilled using the distillation unit. The same technique was carried out for 6 and 9 days fermented in the source grapes and barley, and distilled using the distillation unit. The obtained distilled product was taken and stored at cool temperatures around 10 to 11 degrees Celsius. Now the same process was carried out by the irradiated yeast, here before adding the yeast into the source the yeast saccharomyces cervasie was been irradiated using UV light. The yeast has been transferred into the distilled water into 3 different petriplates, and irradiated under UV light with different length and time 3cm, 6cm, 9cm and time 2min, 4 min, 6 min. Using the irradiated yeast the fermentation process was carried out as with normal yeast at different days. The production was so high for certain range of time but getting degraded due to the degradation of source as it is batch fermentation. After the complete fermentation process, the amount of yield was tested using the biochemical test. But surprisingly the amount of yield was high with the process carried out by the irradiated yeast rather with normal yeast.

1-11

Authors: G Ashok kumar

The human intestinal tract has been colonized by a large number of types of microorganisms amid the coevolution of man and organisms. Gut-borne organisms dwarf the aggregate number of body tissue cells by an element of ten. Late metagenomic examination of the human gut microbiota has uncovered the vicinity of almost 3.3 million qualities, when contrasted with the simple 23 thousand qualities show in the cells of the tissues in the whole human body. Proof for different gainful parts of the intestinal microbiota in human wellbeing and malady is extending quickly. Irritation of the intestinal microbiota may prompt endless ailments, for example, immune system sicknesses, colon diseases, gastric ulcers, cardiovascular illness, useful entrail maladies, and heftiness. Reclamation of the gut microbiota may be hard to achieve, however the utilization of probiotics has prompted promising results in an expansive number of very much composed (clinical) studies. Microbiomics has impelled a sensational increment in logical, modern, and open enthusiasm for probiotics and prebiotics as could reasonably be expected operators for gut microbiota administration and control. Genomics and bioinformatics devices may permit us to build up robotic connections among gut microbiota, wellbeing status, and the impacts of medications in the person. This will ideally give points of view to customized gut microbiota administration.

1-17

Authors: Shanker DM

Cell signaling and signal transduction are very important for a cell so that it can govern basic and advanced cellular activities in a well-coordinated manner. The activities of cells include anabolic and catabolic activities, response to their microenvironment and external environment, response to various ligands either beneficial for cell or harmful for cell and other physiological activities (sight, touch, taste, pain, anxiety, anger etc). Transduction involves the binding of extracellular signaling molecules and ligands to cell-surface receptors that trigger events inside the cell. Among the various types of receptors studied GPCRs are considered to be of utmost importance. The members of this large family of proteins are activated by a spectrum of structurally diverse ligands, and have been shown to modulate the activity of different signaling pathways in a ligand specific manner. They play a key role in regulating cell activity and physiological function. GPCR malfunction is responsible for a wide range of diseases including nephrogenic diabetes insipidus, and hyperthyroidism and a large proportion of drugs on the market target these receptors. The knowledge of GPCRs structure and function is very important for elucidating the molecular mechanisms underlying effective signal transduction and diseases and for performing structure-based drug design. Since structural data are restricted to only a handful of GPCRs, a major population of researchers is engaged in deducing the structures of various GPCRs. The main aim of this text is to introduce the fundamentals of GPCRs with emphasis on structure and function of rhodopsin, a well studied GPCR belonging to the rhodopsin family of GPCR and responsible for vision in vertebrates.

1-4

Authors: Taagore Anandakumar B

Earlier the transformation used to take place for only unicellular organisms but nowadays the transformation takes place to multicellular organisms too. Many multicellular organisms have undergone transformation successfully such as drosophila, mice etc. The most common methods of genetic transformation are the plasmid method [1], the vector method and the gene gun method. The vector method and the plasmid method have a lot in similarity the vector method is used extensively like the plasmid method.

1-8

Authors: Hong-Ye Zhao, Hong-Jiang Wei

The currently observed cloning efficiency is low and can be calculated using different methods. Therefore, a reasonable evaluation method for calculating the cloning efficiency in pigs is important for promoting the application of gene-modified miniature pigs in biomedical fields. In this study, we proposed a method for the scientific evaluation of cloning efficiency in pigs based on the production of cloned Diannan miniature pigs. Of 9 recipient gilts that were transferred with cloned embryos, 8 (88.9%) gilts became pregnant, and 7 (87.5%) of these delivered 37 piglets, 22 (59.5%) of which were alive and 17 survived to adulthood (over 1 year of age). Among the 15 stillborn piglets, 11 piglets experienced intrapartum death due to dystocia, and the other 4 died due to blastocolysis at the late stage of pregnancy. The greatest number of littermates was 11 piglets. The 3 piglets delivered by Caesarean section were alive and healthy. The procedure used for cloning pigs is a costly process in terms of both time and money; specifically, it requires 677.7-1265.4 min and $715.8-764.5 to transfer 50-400 cloned embryosto a recipient. The cloning efficiency defined as the total number of cloned piglets (including dead and mother piglets) divided by the total number of transferred embryos was 0.93%, whereas the cloning efficiency obtained based on the total number of live piglets divided by the total number of recipients was 2.44 piglets. The value is higher than those previously obtained using 19 different types of donor cells. These findings suggest that donor cells derived from Diannan miniature pigs are a valuable cell source for somatic cell nuclear transfer and the definition of cloning efficiency in pigs as “the total number of live cloned piglets divided by the total number of transferred recipient gilts” may be a reasonable scientific strategy.

1-8

Authors: Hongwei Rong1

To reveal the effect of dissolved oxygen (DO) on microorganism community structure during simultaneous nitrification and denitrification (SND) in sequencing biofilm batch reactor (SBBR), the molecular biological techniques of denaturing gradient gel electrophoresis (DGGE), cloning and real-time PCR were applied. DGGE sequence analysis showed some kinds of populations had been highly preponderance consistently, and cloning and phylogenetic tree of AOB gene revealed Nitrsospira was dominant species. The real-time PCR analysis indicated that the amount of the AOB and NOB both had most copy number in the lower surface, and the quantity relation of AOB and NOB population between three samples was “lower surface＞upper surface＞internal layer”. The result proved that DO concentration directly affected the proportion of aerobic fraction and anoxia fraction in the biofilm, which led to an effect on efficiency of SND.

1-9

Authors: Qingsen Chen

Objective: To explore the regulatory role of Casein glycomacropeptide (CGMP) in the fecal flora of mice with Ulcerative colitis (UC). Methods: The BALB/c mice were divided into a normal control group, a model group, CGMP groups with low doses (5 mg/kg·d), middle doses (50 mg/kg·d) and high doses (500 mg/kg·d), and a Sulfasalazine (SASP) group. Except the normal control group, all mice were treated with Oxazolone (OXZ) by perfusion to induce the UC model. In contrast, the mice in the normal control group and the model group were treated with an equal volume of saline for 7 consecutive days, which the changes in the fecal flora of the mouse intestines were evaluated by Fluorescence in situ hybridization (FISH) and DNA staining. Conclusion: CGMP can rectify the structural imbalances in the colon fecal flora in mice with UC and can improve the proportion of dominant flora in the intestine. CGMP at a dose of 50 mg/kg·d can significantly reduce the number of Enterobacteriaceae and Enterococci and promote the proliferation of Bifidobacteria, Lactobacilli, Bacteroides and Clostridium coccoides in the intestine.

1-8

Authors: Hong-Ye Zhao, Hong-Jiang Wei

The present study investigated the effect of delipation (lipid droplet removal) on the developmental competence of porcine oocytes. Delipated (+/−) and/or vitrified (+/−) oocytes were subjected to parthenogenetic activation, the viability of the early parthenogenetic embryos was recorded, and the embryos were then transferred to recipients for further development. The results showed that the cleavage and blastocyst rates of the parthenogenetic embryos from the early delipated oocytes were significantly lower than those of embryos from a control group (undelipated oocytes) (P<0.05). After transfer to recipient pigs, these embryos were able to further develop and to produce parthenogenetic fetuses. Using the minimum volume cooling (MVC) method, the parthenogenetic embryos from early delipated oocytes could be cryopreserved by vitrification at 1-cell to early blastocyst stages. After thawing, the early blastocyst stage was found to be optimal for vitrification. Also embryos vitrified at 2-4 cells derived from early delipated oocytes were transferred into two recipient pigs, and resulted in limb-bud stage fetuses. In conclusion, the results demonstrated that parthenogenetic fetuses can be produced from porcine embryos before or after vitrification by a strategic combination of in vitro-matured (IVM) oocyte delipation with vitrification at any early embryonic developmental stage. This approach may have application to cryopreservation of cloned and intracytoplasmic sperm injection (ICSI) embryos derived from delipated oocytes.

1-8

Authors: Luciana Konecny Kohn

The Hepatitis C virus (Flaviviridae family, Hepacivirus genus) represents a major public health problem worldwide and it is responsible for chronic infections in humans, which can develop to liver cirrhosis and hepatocellular carcinoma. As this virus does not replicate efficiently in cell culture and in animals, bovine viral diarrhea virus (BVDV) is used as a surrogate model for screening assays of antiviral activity, and mechanism of action assays. From marine invertebrates and their microorganisms isolated, we prepared extracts and fractions, and we isolated substances for assessment of their possible antiviral activity. Of the 71 tested, seven were considered promising presenting protection percentage of more than 80%. The best inhibition results were obtained from the extracts produced by the Gordonia bacteria samples with 99.9% inhibition and by Micrococcus with 99% inhibition. Furthermore, most of the extracts selected by the protection percentage showed selectivity index values considered promising, especially the extracts of the bacteria Williansia (SI=27) and Brachybacterium (SI=39). On the action mechanism, most of the promising extracts showed activity in the inhibition of intracellular replication steps, although it has been observed action of different extracts in several stages of viral replicative cycle. Thus, various extracts stood out and may lead to the development of drugs that ensure an alternative therapy for the treatment of hepatitis C.

1-5

Authors: P Ellaiah

During our continuous search for antibiotic producing actinomycetes, a variant of Streptomyces species was isolated from soils of Andhra Pradesh in India. The morphological, cultural, physiological and biochemical characters were studied, compared to known species and identified as a new variant of Streptomyces noursei and designated as Streptomyces noursei var saccharicus. The antibiotic activity of the strain was tested against both Gram-positive and Gram-negative bacteria as well as fungi and yeasts. INTRODUCTION Since the isolation of actinomycin in 1940 and streptomycin in 1944 by Waksman, the actinomycetes have received tremendous attention of the scientists. Soils, composts and fodders are common sources of actinomycetes. Waksman [1] recognized a few natural substrates as ideal sources for the isolation of actinomycetes and other streptomycetes. The nature of a Streptomyces colony is an important property in characterizing a culture. Krainsky [2] used the structure, size, shape and texture of the colony as one of the major diagnostic criteria. According to Pridham and Lyons [3] and International Subcommittee [4], the best way to handle streptomycete classification nomenclature and identification is through application of the genus-species-subspecies concept. The majority of antibiotic producing actinomycetes found in these species led to growing economic importance of these organisms which resulted in the isolation and description of numerous new species. It is reported that the only genus Streptomyces, the member of Actinomycetales accounts for approximately 93% producing secondary metabolites [5]. The present communication deals with the isolation and characterization of an antibiotic producer from soils.

1-6

Authors: Mustafa Baloch

Nowadays, natural treatment of bacterial diseases using substances which are herbal is of utmost importance. In the present study effects of three antibacterial medicinal plants in south of Iran against the separated Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli from Clinical samples and standard strains was investigated. Hydro-alcoholic extracts of Ziziphora tenuior, Origanum Vulgare and Mentha longifolia were prepared after being dried at shade. In the following the antibacterial activity of the extracts against separated Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli from clinical samples of the Shiraz hospitals and standard samples using disk agar diffusion method was investigated and the drug resistance in the studied samples was conducted using the standard Kirby-Bauer method. The growth of the all studied Staphylococcus aureus and Escherichia coli was stopped by hydro-alcoholic extracts of Mentha longifolia, Ziziphora tenuior and Origanum Vulgare but Pseudomonas aeruginosa showed growth zone of inhibition only against Origanum Vulgare. From statistical viewpoint Origanum Vulgare had also the most antimicrobial effect against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli in the all studied samples (P<0.05). Extracts of Mentha longifolia, Origanum Vulgare and Ziziphora tenuior have a potent antibacterial effect against the gram-positive and gram-negative. But on the nosocomial pathogen, Pseudomonas aeruginosa, only Origanum Vulgare has growth inhibitory effect.

1-4

Authors: Barge VU

Chromatography, although primarily a separation technique, is most employed in chemical analysis in biotech plant is SEC which is very powerful technique for protein purification, polymer characterization etc. As the principal advantage of SEC is its gentle non-interaction with the sample, enabling high preservation of biological activity, so SEC has lot of importance in biotech industry. In this review the basic theory, principle & applications of SEC in biotech industry are included.