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A potential glycolipid biosurfactant producer Streptomyces sp. MAB36 was isolated from marine sediment samples. Medium composition and culture conditions for the glycolipid biosurfactant production by Streptomyces sp. MAB36 were optimized, using two statistical methods: Plackett-Burman design was applied to find out the key ingredients and conditions for the best yield of glycolipid biosurfactant production and central composite design was used to optimize the concentration of the four significant variables, starch, casein, crude oil and incubation time. Fructose and yeast extract were the best carbon and nitrogen sources for the production of the glycolipid biosurfactant. Biochemical characterizations including FTIR and MS studies suggested the glycolipid nature of the biosurfactant. The isolated glycolipid biosurfactant reduced the surface tension of water from 73.2 to 32.4 mN/m. The purified glycolipid biosurfactant showed critical micelle concentrations of 36 mg/l. The glycolipid biosurfactant was effective at very low concentrations over a wide range of temperature, pH, and NaCl concentration. The purified glycolipid biosurfactant showed strong antimicrobial activity. Thus, the strain Streptomyces sp. MAB36 has proved to be a potential source of glycolipid biosurfactant that could be used for the bioremediation processes in the marine environment.

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The aim of the present study was to elucidate the anti-diabetic effects of the crude polysaccharide and rhamnose-enriched polysaccharide derived from G. lithophila on streptozotocin (StZ)-induced diabetic Wistar rats. Treatment with crude polysaccharide and rhamnose-enriched polysaccharide showed increases in body weight and pancreatic insulin levels and a decrease in blood glucose levels compared with control diabetic rats. The blood concentrations of total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) decreased, and highdensity lipoprotein (HDL) increased both in the crude polysaccharide-and rhamnose-enriched polysaccharide-treated rats. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels increased, and malondialdehyde (MDA) levels decreased in the livers, kidneys and pancreases of crude polysaccharide-and rhamnose-enriched polysaccharide-treated rats. Immunohistological examination further confirmed that restoration of the normal cellular size of the islets of Langerhans and the rebirth of β-cells were found to be greater in the body region than in the head and tail regions of the pancreas. the crude polysaccharide-and rhamnose-enriched polysaccharide-treated diabetic rats showed normal blood glucose levels and insulin production, and reversed cholesterol levels and enzymatic actions. Therefore, rhamnose-enriched polysaccharide from G. lithophila acts as a potent anti-diabetic agent to treat diabetes and can lead to the development of an alternative medicine for diabetes in the future. Diabetes and other associated diseases are major health problems in modern society. Both type 1 and type 2 diabetes comprise abnormalities of insulin action, which includes insulin insensitivity and resistance 1. Diabetes mellitus (DM) is a group of heterogeneous, hormonal and metabolic disorders characterized by hyperglycaemia and glucosuria, with disturbances in carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both 2. Diabetes mellitus is associated with long-term complications such as retinopathy, nephropathy, neuropathy and angiopathy. Furthermore, DM is considered a major risk factor for cardiovascular disorders, namely, ischaemic heart disease, cerebral stroke and peripheral artery disease, leading to increased mortality of patients with diabetes 3. In recent times, the most challenging diseases faced by health care professionals are diabetes and other associated disorders. Their increasing prevalence adds a large burden to society and the public health sector 4. Globally, approximately 171 million people have been affected by diabetes since 2000 5. The estimated incidence of DM for

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