Current Biochemical Engineering (Discontinued) - Volume 4, Issue 1, 2017

Reduce, Reuse, Recover, Recycle and Remanufacture are the 5R’s which are of utmost priority in the current era. The country could profitably utilize 65% of the waste in producing energy and to compost, another 10 – 15% to promote recycling industry and bring down the quantity of waste going to dumps and landfills to 20%. India is the second fastest growing economy and the second most populated country in the world. As the population is increasing day by day, the solid waste generation is also increasing. “More is the population, most is the municipal solid waste generated (MSW).” Most of the MSW generated consists of domestic waste like kitchen waste (fruit and vegetable waste, junk food, bakery items etc.), recyclables and inert. Efforts need to be taken to ensure proper reuse or recycling of the organic fraction of MSW (OFMSW). The aim of this study is to focus on the opportunities associated with food waste-to-energy and to estimate the production of biogas from waste in popularising the decentralized biomethanation systems at commercial scale. This includes a techno-commercial understanding of the technology and its relevance to the Indian scenario.

Combinatorial chemistry has rapidly evolved from its interest in the generation of large number of compounds for the discovery of actives amongst them in random screening procedure to a powerful designed combinatorial technology for the creation and optimization of pharmaceutical lead compounds to produce drug candidates. The introduction of solid phase synthesis methods has rich impulse in this field, through automation and miniaturization. This review summarizes the present techniques of solid phase synthesis associated with combinatorial chemistry. The conventional methods for the synthesis of peptide libraries on solid support are split and mix synthesis, pre-mixed synthesis and parallel synthesis. In order to fulfil the increasing demand of synthetic peptides, several techniques have been developed, for example, pin synthesis, tea-bag synthesis, photolithography, SPOT synthesis, microchip synthesis, nanotechnology, lab-on-a-chip and bioinformatics and further their deconvolution to access the contribution of every peptide to the desired biological activity. This review also discusses about the combinatorial peptide library characterization and purity as well as their applications in drug development.

Enzymes are important biocatalysts that exist naturally in all living organisms. Nowadays, enzymes have been widely applied to modern industries because biological catalysts are substratespecific, highly active and operate within mild environments. However, the cost of culturing proteinrich microorganisms as well as extracting and purifying the enzymes are high. One solution is to genetically modify the microorganisms for high protein expression. Therefore, this review discusses the mechanism of various mutagenesis techniques (physical and chemical) as well as the potential genetic modification to increase protein yields in microorganisms.

Background: Recent energy scenario shows that there must be a scarcity of fossil fuel occurs in future decades, simultaneously the usage of fossil fuels encountered in environmental hazards. Therefore, alternate sources are in demand to harvest fuel. This could be availed by an alga in forth coming years by exploiting the establishment towards biofuel production. Among the numerous alga species, Chlorella pyrenoidosa is identified as a potential strain for fuel production. This work is proposed to enhance the growth and fatty acid content of Chlorella pyrenoidosa in a batch culture system for biodiesel production. Objective: The growth response of Chlorella pyrenoidosa attained by varying the major factors which includes sodium bicarbonate, cultivation time and inoculum concentration by using a Central Composite Rotatable Design -Response Surface Methodology (CCRD-RSM). Method: A design-expert 9 tool was used to optimize dependent variables and to identify the independent response for the process. Moreover, the functioning parameters have been optimized in a batch culture system using five level points of CCRD – RSM. Results: A high lipid content of 193.9 mg/L was obtained in 22nd day of culture has been grown at 8 % of seed culture and 6671 mg/L of sodium bicarbonate concentration, which evidently illustrates that the aforesaid factors are the optimal range of operating conditions which need to be considered in a high content of lipid. Furthermore, Gas Chromatographic analysis of lipids extracted from the biomass has shown a high yield of saturated and unsaturated methyl ester fatty acids such as 61.54 % of palmitic acid, 20.95 % of stearic acid and 17.51% of arachidic acid, respectively. Conclusion: Henceforth, this study affirms that the Chlorella pyrenoidosa touts green algae for biofuel production.

Background: In this research, guava leaves are utilised as a potential source of natural antioxidants. Various extraction techniques have been applied for the extraction of phenolic compounds from plants. However, the high temperature and long extraction time used in these methods can cause degradation of the bioactive compounds. In order to overcome this limitation, ultrasound assisted extraction is one of the techniques that can be applied. The advantages of this method include increased extraction yield, less solvent amount required, lower temperature and shorter extraction time. Objective: The main objective of this work is to apply ultrasound assisted method in the extraction of antioxidant from guava leaves. The effect of extraction time, temperature and the solid-to-liquid ratio on the extraction performance are investigated. Method: The extraction was conducted by following the standard method described in the literature. Total phenolic content and antioxidant activity were analysed according to Folin-Ciocalteu and 1,1- Diphenyl-2-picryl-hydrazyl (DPPH) method, respectively. Results: The results show that both total phenolic content and antioxidant activity increase with an increase in extraction time. The most appropriate temperature was found to be 55 °C, while increasing the solid-to-liquid ratio led to a drastic drop in the phenolic content and the antioxidant activity of the guava leaves. Conclusion: The ultrasound assisted extraction method was successfully applied in the extraction of antioxidant compounds from guava leaves. The utilisation of guava leaves in this manner is expected to reduce the amount of waste disposal from food industries.

Background: The potential of a material that has received little attention, namely wastewater screenings produced during wastewater treatment, was examined for recovering valuable products, in the form of methane and phosphorus, in order to turn this waste into useful resources. Anaerobic digestion was performed to recover biogas that has sustainable energy in the form of methane as its main component. The nutrient released in the residual digested liquor can then be precipitated as struvite, which allows its recovery as phosphorus, which is reported is depleting. Objectives: This study aims to examine the potential of wastewater screenings for biogas and phosphorus recovery through anaerobic digestion and phosphorus precipitation. Methods: Wastewater screenings were subject to anaerobic batch digestion at a range of dry solid concentrations to determine the biochemical methane potential. The anaerobic digestion was performed at mesophilic condition of 37oC for 30 days at maintained pH6.8-7.2. The digestate was then analysed for its struvite potential, which permitted the theoretical amount of struvite precipitation to be determined by molar balance calculation. Results: The optimum dry solids concentration for methane was of 6% when methane yield of 0.355 m3CH4/kg VS was achieved. By contrast a lower dry solids concentration of 3% was optimal for phosphorus recovery when 0.27g struvite/g dry solids was achieved. Conclusion: Wastewater screenings can provide a valuable source of methane and phosphorus, which are not exploited by current landfill disposal practice. By performing anaerobic digestion on screenings, it’s not only to alleviate environmental problems but also to recover depleted resources.