Microbial Polyhydroxyalkanoates Granules: An Approach Targeting Biopolymer for Medical Applications and Developing Bone Scaffolds

Microbial polyhydroxyalkanoates (PHA) are proteinaceous storage granules ranging from 100 nm to 500 nm. Bacillus sp. serve as unique bioplastic sources of short-chain length and medium-chain length PHA showcasing properties such as biodegradability, thermostability, and appreciable mechanical strength. The PHA can be enhanced by adding functional groups to make it a more industrially useful biomaterial. PHA blends with hydroxyapatite to form nanocomposites with desirable features of compressibility. The reinforced matrices result in nanocomposites that possess significantly improved mechanical and thermal properties both in solid and melt states along with enhanced gas barrier properties compared to conventional filler composites. These superior qualities extend the polymeric composites’ applications to aggressive environments where the neat polymers are likely to fail. This nanocomposite can be used in different industries as nanofillers, drug carriers for packaging essential hormones and microcapsules, etc. For fabricating a bone scaffold, electrospun nanofibrils made from biocomposite of hydroxyapatite and polyhydroxy butyrate, a form of PHA, can be incorporated with the targeted tissue. The other methods for making a polymer scaffold, includes gas foaming, lyophilization, sol–gel, and solvent casting method. In this review, PHA as a sustainable eco-friendly NextGen biomaterial from bacterial sources especially Bacillus cereus, and its application for fabricating bone scaffold using different strategies for bone regeneration have been discussed.

BIODEGRADABLE PLASTIC (PHB) FROM BACTERIA COLLECTED FROM GOPALPUR BEACH, BHUBANESWAR

Objective: Environmental concerns have prompted research into the development of biodegradable polymer as an alternative to petroleum-based plastics. Polyhydroxybutyrates (PHBs) are good alternatives to produce biodegradable plastics. Some bacteria are found to be producing PHB. The aim of this work was to isolate potential PHB producing bacteria and screen them for their ability to produce PHB. Methods: Contaminated water sample from Gopalpur beach, Bhubaneswar was the source of bacteria. Three colonies were isolated from the water sample. The samples were named as C1, C2 and C3. The colonies were first identified by colony morphology. The sudan black screening test was done to screen for the production of (PHB) polyhydroxy butyrate by bacterial isolates. Results: The bacterial isolates C1 and C2 showed a positive result for the production of polyhydroxy butyrate (PHB). Presence of PHB granules in Cocobacillus and Rod shaped bacillus was confirmed. Conclusion: Polyhydroxybutyrate (PHB), a kind of microbial polyester that accumulates as a carbon/energy reserve material in various microorganisms, was thus concluded to be a decent alternative for plastics. Because of their special characteristics and broad biological applications, biodegradable plastics are compounds with a promising future.

Polyhydroxybutrate Production Using Groundnut Shell as Substrate by Bacillus circulans (MTCC 8167)

Groundnut shell is considered to agro-industrial waste product and is rich in lignocellulose materials. It is obtained after the removal of groundnut seed from its pod and used as fodder for cattle. Duc et al., (2019) elaborately reviewed beneficial uses groundnut shells for commercial and industrial purposes and listed production of various bio-products such as biodiesel, bioethanol, and nano-sheet. The aim of this work was to study the production of polyhydroxy butyrate (PHB) using groundnut shells as the carbon source after hydrolysate. Groundnut shell was pre-treated with alkaline reagent with 0.5M, 1M, and 1.5M, of potassium hydroxide and acid hydrolysis with 30%, 50%, and 70%, of sulphuric acid. Combined alkali (1M of potassium hydroxide) and acid (70% sulphuric acid) pre-treatment of groundnut shell yield maximum reducing sugar. In addition, with pre-treated groundnut shell, various pH level (6, 7, & 8), KH2PO4 (100mg/l, 200mg/l and 300mg/l), and temperature (250C, 300C and 350C) are also test for PHB production. Bacillus circulans (MTCC 8167) significantly utilized the hydrolysate substrate and produced the maximum amount PHB (7.6 ± 0.2 g L-l) with pH level 7 and 300C with 100mg/l of KH2PO4. A detailed study of the functional group was also done using FTIR and NMR. Through biochemical pre-treatment, an in-expensive groundnut shell was converted into a valuable bio-product in order to achieve the minimum waste production.

The effect of nauplii Artemia sp. enriched with biofloc on the performance of Penaeus monodon and Penaeus vannamei post-larvae

Artemia sp. is a common natural feed for shrimps at the post-larvae stage and is characterized by poor lipid content. Therefore, Artemia is commonly enriched with specific nutrition, including biofloc. This contains some useful nutrients in the form of protein and polyhydroxy butyrate (PHB). The aim of this study was to analyze the effect of Artemia enriched with biofloc on the growth performance of black tiger shrimp, P. Monodon, and whiteleg shrimp P. vannamei. This research used acompletely randomized design (CRD), encompassing three treatments of feed and four replications. The tested treatments include: (a) Artemia sp. without enriched (b) Artemia enriched with biofloc, and (c) biofloc without Artemia, and the treatments were fed on black tiger as well as whiteleg shrimp post-larvae for 15 days. The results showed the significant effect of using Artemia sp. enriched with biofloc on the growth of P. monodon and P. vannamei, but not on the survival rate. However, both parameters were significantly influenced for post-larvae shrimp at a dose of 30 mL biofloc. This served as a nutritional source by providing the best growth of 14.57 mg and 15 mg at a daily growth and survival rate of 0.86 mg day-1: 98% and 1.4 mg day-1: 99% for P. vannamei and P. monodon, respectively.