Current Biochemical Engineering (Discontinued) - Volume 5, Issue 1, 2019

Background: The world’s annual utilization of plastic materials is growing day by day and simultaneously solid waste management is becoming one of the major environmental concerns throughout the world. Current approach for their usage and disposal is not sustainable because of the durability of the polymers involved. Methods: Partially digested products of these plastics in the form of micro-plastics are accumulating as debris in landfills and in natural habitats because of their remaining in the environment for millions of years. Easy availability, low cost and ubiquitous applications make the plastics most attractive polymer whose proper disposal through specific technology seems the only alternate and that may lessen down the pollution over the next decades. Results: Recycling as a waste management strategy provides opportunities to reduce the use of petrochemical resources and improving environmental conditions. Reuse of bulky plastic wastes in concrete and Wood Plastic Composites (WPC) seems a smart approach for solving the problem of disposal. The development of new construction materials using recycled plastics is important to both the construction and the plastic recycling industries. Conclusion: This review article presents the details of recycling of waste management, their probable application for concrete and WPC production, types of recycled plastics, role of microbes and microbial enzymes for recycling of plastics and emphasis on use of biodegradable plastics to make the environment green.

Background: The proposal to perform scale-down of culture systems (2 to 4 mL) could be more efficient for screen multiple formulations and operational conditions. For such, is important to evaluate if the kinetic parameters of a bioprocess are comparative to conventional lab-scale reactors. In the present study, the effects of different miniaturized systems were evaluated on growth and lipase production of Yarrowia lipolytica IMUFRJ 50682. Methods: Cultivations were conducted in a mini-scale version of Erlenmeyer flask of 10 mL (10EF); 24 deep-well microplate of 11 ml (24MTP/11 mL) and 24 deep-well microplate of 25 ml (24MTP/25 mL). Results: Similar specific growth rate (μ) was observed between miniaturized cultivations (0.27 h-1). Different lipase productivities values were obtained, the highest was achieved in 10EF (181 U.L-1.h-1). Volumetric oxygen transfer coefficient (kLa) and maximum lipase production were improved with culture miniaturization in comparison with conventional shake-flasks. Bioreactor (1.5 L) cultivation showed similar growth kinetic, pH profile and kLa values, but an increase in the maximum productivity was observed. These finding showed the advantages of Y. lipolytica cultivations scale-down. Conclusion: These findings show the advantages of Y. lipolytica scale-down cultivations, and to perform scale-up for benchtop bioreactor directly from these miniaturized cultivations, without the need of gradual scale-up, representing a reduction in costs and working time. Taking into consideration the rare works about miniaturized cultivation with Y. lipolytica, this work opens the way to a better understanding of bioprocess and alternatives for process conduction.

Background: North east region of India is well known as biodiversity hotspot with endemic flora and fauna. Organisms belonging to the cyanobacterial species are commonly known as blue green algae and are found in diverse categories in the environment of north-east India. Potentials of these cyanobacterial species are mostly unexplored. Present study aimed to isolate, identify and evaluate the potential cyanobacterial strains for the sustainable producers of biomolecules with agricultural, therapeutic and industrial significance. Methods: Growth and biochemical characterization were performed with the isolated cyanobacterial species to investigate the growth kinetics, cellular pigments (carotenoid, phycobiliprotein and chlorophyll), protein, carbohydrate and lipid content. Results: Three Phormidium sp., one Oscillatoria sp., and one Microcoleus sp. were isolated from the Tripura state (North-east region of India). Results revealed that isolated Oscillatoria sp. has high lipid (~20%), protein (~40%), and carbohydrate (~30%) yield. Further, two isolated Phormidium sp., produced significant amount of carotenoids (~23 mg/gm dry biomass), phycobiliprotein (~20-25%) and high protein (~55%). Microcoleus sp. produced 62% carbohydrate and 20% phycobiliprotein with significant amount of carotenoids (~17 mg/gm dry biomass). Conclusion: Isolated Oscillatoria sp. is the promising resource for lipid and nutritional supplement due to high accumulated primary metabolites. Two Phormidium sp., can be used as animal and human nutritional food supplement and also can be further investigated for pigment production at industrial scale. Isolated Microcoleus sp. is the potential resource of carbohydrate and pigment. Isolated cyanobacterial strains are identified as viable candidates for the industrial production of biomass as well as other value added biomolecules.

Background: Packing materials, which are used in biofiltration systems treating gaseous volatile organic compounds, are expected to have optimal water content in their actual use. This is because high volume of water increases the diffusion resistance while low water content decreases microbial activity. Therefore the thickness of the liquid layer on the packing material needs to be identified to determine the mass transfer process of target pollutants. However, it cannot be measured directly due to the complicated surface structure of general packing materials. Methods: In this study, ideal biofiltration surfaces were prepared artificially by coating a plain membrane surface with mono-cultured biomass and a known thickness of liquid layer. The sorption velocity of gaseous toluene was then observed, within a considerable range of liquid thicknesses, on this biomass surface. The velocity of water vaporization from a porous PVF poly-vinyl formal (PVF) material was then measured. Finally, the relationship between thickness of liquid surface and the water content of the PVF material was calculated based on the experimental results and a set of mathematical models on vaporization. Results: There is an appropriate range for the thickness of the water layer thickness on the biomass at the surface of packing material. In one case, this thickness was cited as approximately 0.1–0.2 mm for gaseous toluene. The PVF material was thought to form such a thick water layer at around 50–60% of its water content. The water content conditions that affect the formation of the water layer changed when biomass grew on the surface of the PVF material. The range declined from around 70% for new material to around 55% for biomass-rich material. Conclusion: This study quantitatively clarified the reason why there is optimal range of water content for the packing material of biofiltration; i.e., appropriate liquid layer thickness at the surface of packing materials is built by a certain range of water content.

Background: Jicaro seeds can be considered oilseeds due to their high content of lipids, which could be used. Aqueous Enzymatic Extraction (AEE) of oils is a safe, economical and ecological technique, with the disadvantage that oil yields are lower than conventional methods. The microwaves pre-treatment of the seeds has been applied to overcome this inconvenience. Therefore, the objective of this study was to investigate the aqueous enzymatic extraction of oil from Jicaro seed pretreated in a microwave (M-AEE) compared to Soxhlet extraction, in terms of oil yield and its quality. Methods: M-AEE was evaluated varying type of enzyme, extraction time, enzyme concentration, solid/liquid ratio and particle size, according to Fractional Factorial experimental design. The obtained oil was analyzed in terms of fatty acid content and antioxidant activities. The same analyses were performed in oil obtained by Soxhlet extraction for comparison. Results: All parameters investigated in this work had a positive effect on the extraction process. The highest oil yield of 69.71% was obtained with a particle size of 0.59 mm, 3% (w/w) of Viscozyme L, solid/ liquid ratio of 1:6, and 5 h. No differences were found in fatty acid content and antioxidant activity between the oil obtained by M-AEE and that obtained by SE. Conclusion: The properties of the oil were not different in the two extraction methods evaluated; however, M-AEE has the advantage of being environmentally friendly technique. Jicaro seed oil physicochemical properties were similar to edible oils, thus could be considered as a new option of edible vegetable oil.

Background: The Terminalia arjuna has been reported for the antimicrobial activity using classical methods of extraction in the literature. As novel extraction methods have gained importance to carry out the extraction of different plant materials, hence it was planned to extract Terminalia arjuna stem bark in a better way and evaluate the change in antimicrobial activity of the improved extracts. Objective: The extraction and evaluation of antimicrobial activity of stem bark of Terminalia arjuna were performed, analyzed and compared using different extraction methods viz. RTE, SE and USAE in this article. Methods: The central composite design among the response surface methods was adopted to carry out the optimization of different parameters of ultrasound-assisted extraction. The central composite design was used for optimization and the values of parameters for an optimized batch of ultrasoundassisted extraction were 800 W power, 10 minutes time and 1:80 ratio of solid/solvent ratio. The invitro antimicrobial activity was performed using the tube dilution method taking ciprofloxacin and fluconazole as standard antibacterial and antifungal agents. Results: The value of estimated total percentage yield was 12.8 % which upon experimentation was obtained as 12.7 %. The extraction efficiency of USAE was found better as compared to the RTE and SE in terms of the extraction yield 4.2% and 6.8 % respectively. The extraction time of the conventional RTE and SE (2 days and 7 days) was also reduced to minutes (10 to 20 min.) in USAE hence was found to be better. The antimicrobial activity of the selected extracts was performed using tube dilution method on selected strains of bacteria S. aureus, B. subtilis, E. coli and fungal A. niger and C. albicans. The results obtained suggested that the USAE technique showed best results as compared to the other extraction methods and the standard drugs taken (MIC values of 3.12, 1.56, 3.12, 1.56 and 3.12 μg/mL respectively). Conclusion: Hence, it was concluded that ultrasound is an effective technique of extraction and has enhanced the antimicrobial principles of the Terminalia arjuna stem bark.

Background: Eutectic solvents are a mixture of two compounds which possess a lower melting temperature than the parent compounds, using quaternary ammonium salts, such as choline chloride and betaine hydrochloride and organic acids, polyols and amides as hydrogen bond donors. These solvents can be an alternative as non-aqueous media for enzymatic reactions, mainly using lipases. Objective: The objective of this work is to evaluate enzymatic activity and stability of commercial lipases, immobilized or at free form (Thermomyces lanuginosus: Lipozyme TL IM, iTL and Lipolase 100 L, fTL; Candida antarctica: Novozym 435, iCALB; Novozym 735, iCALA and Novozym CALB L, fCALB); and a phospholipase (Lecitase Ultra), in the presence of eutectic solvents (choline chloride ChCl:urea, ChCl:glycerol, betaine hydrochloride (BeHCl):urea and BeHCl: glycerol. Methods: Initially, lipases were maintained for 2 hours in solutions of choline and betaine-based eutectic solvents (1 to 20% m/m) at 25ºC compared with water for relative enzymatic activity. Using the solvent that best promoted lipase activity, some parameters were evaluated such as the molar ratio between quaternary ammonium salts and urea, stocking temperature and kinetics. Results and Conclusion: These eutectic solvents enable, mainly with immobilized lipases, 25 to 125 times more activity than water at 25ºC and 2h, and even after 24h, lipase iTLL was still 40 times more active in the presence of ChCl:Urea 1:3. Lipase iCALB showed great thermostability 47 times higher at 55ºC, almost double relative activity at 25ºC in the presence of BetHCl:Urea 1:4.