Current Biotechnology - Volume 5, Issue 4, 2016

Background: Algae are currently considered among the most promising sources of raw materials for biodiesel production. Exceptional characteristics of some algal species and strains allow to reach more than 80% of neutral lipids; meanwhile, it should be taken into account that algal cultures do not need arable lands, they are undemanding to the sources of nutrition, being able of fast accumulation of biomass, and having a number of other advantages. However, if the aim is to get price-competitive raw material from them, it is not enough just to select natural strains - it is necessary to apply additional efforts to improve useful characteristics of these organisms. In-depth understanding of the lipid metabolism pathways in bacterial and eukaryotic cells has already allowed transferring this knowledge to microalgae in order to manipulate the expression of key genes responsible for enhancing their cellular oil content and oil quality. This review aims to show how genetic engineering efforts can change quantity and quality of microalgae lipids and make other changes on the transformed cells. Methods: We carried out a goal-directed analysis of bibliographic databases to generalize main results in genetic engineering of microalgae lipids pathways. Deductive qualitative content analysis methodology was used to analyze the papers. Results: Results of different methods of algal transformation by constructions that contain genes responsible for metabolism of lipids, which could be influential upon the competitive pathways of lipids biosynthesis and biosynthesis of their precursors, are compared and discussed. It is concluded that methods of genetic engineering allowed receiving the strains of microalgae with increased capability to accumulate lipids, changing their composition and improving algal growth characteristics. Conclusion: The analyzed data gives a better understanding of the metabolic pathways of lipids in microalgae, the ways of their regulation for the purpose of creating high-technology strains for producing of raw material for biodiesel production using not only traditional genetic engineering approaches, but also through projection of these efforts via extending possibilities of genomic engineering, including the potential of synthetic biology.

Background: Autotrophic microalgae carry out the photosynthetic conversion from light into organic compounds. Microalgal cultivation brings environmental advantages, highlighting the capability of nutrient recycling from wastewater combined with C02 fixation from flue gases towards a wide range of 3G biofuels and bioproducts. These micro-organisms have been widely recognized as having huge potential as feedstock for food and feed industries, as "nutraceutical" agents (carotenoids, antioxidants, polyunsaturated fatty acids, single-cell proteins (SCP), phycobiliproteins, polysaccharides, vitamins, phytosterols, minerals), for the cosmetic industry, bioplastics, agriculture biofertilizers and recently as an energetic vector towards the production of a wide range of biofuels. Microalgae exhibit clear advantages when compared with higher plants, such having a higher photosynthetic efficiency, higher areal biomass productivities, higher C02 biofixation rates from flue gases emitting plants, higher 02 production rates, non-competition for agricultural areas (marginal lands such as deserts, rocky areas and salt pans can be used), non-competition for drinking waters (saltwater, brackish water and wastewaters can be used), harvesting routines can be carried out daily with better equipment and better resource management lowering storage costs. Objective: A brief introduction will be presented on microalgal biotechnology with a special emphasis on economics and production costs to date. The key factors which have strongly affected microalgal biomass and/or their product costs will be analyzed and critically discussed, especially concerning biofuels. Results: Several constraints should be overcome in order to achieve a cost-effective microalgal biofuel production, such as the high energy inputs and the still prohibitive production costs (currently around 5000 /ton, far above the desired threshold target of 500 /ton). The attempts carried out by researchers in the last decades in order to decrease microalgal production costs either by increasing productivities and/or product yields or by cutting production factors (low cost bioreactors, cheap culture media formulations, wastewater treatment, greenhouse gases biofixation and low cost downstream processing) will be revised and discussed.

Background: Algal biofuel production can be made sustainable in partnership with dairy farms, industries and municipal systems for nutrient management requiring waste treatment. Waste streams contain unmined nutrients such as nitrogen, phosphorus, and carbon. The nutrients runoff especially nitrogen and phosphorus pollution can impair water quality of natural water bodies posing environmental threat due to undesirable algae blooms affecting natural aquatic communities. Anaerobic biodigesters can efficiently take care of biochemical oxygen demand to improve water quality but leave behind excess nutrients in the effluent. The excess nutrients can be potentially used for selected algal biomass growth for fuel and co-products. Methods: This paper reviews the algal biofuel systems that can integrate with biodigesters for sustainable cogeneration of renewable energy forms (liquid biofuels, electricity, and heat) so that the waste effluent from dairy farms, municipal and industrial anaerobic digesters, food and beverage and other industries can be combined with the algal biofuel process to produce additional valued co-products including feedstock for biogas, organic fertilizer, and animal feed for generating additional revenues. Conclusion: A successful implementation of a system as described will have multifold higher oil yield from non-food algae biomass compared to food sources (e.g. soybean and corn oil) for biofuel; benefit environment by capturing nitrogen and phosphorus from effluents to reduce environmentally harmful runoff affecting the health of natural water bodies, reduce in the fuel emissions especially the oxides of nitrogen in contrast to both diesel and conventional biodiesel, meet environmental protection regulations with reductions in particulate matter and total hydrocarbons; and bring economic benefits from marketable products across the complete supply chain involved at the sites that implement bolt on algal system with waste management systems for cogeneration of energy.

Background: Aquaculture's pressure on forage fisheries and environmental conservation remains hotly contested and thereby constrains the further development of aquaculture industry. With recent advances in microalgal biotechnology, the utilisation of algae in aquaculture is not only limited in traditional cultivation as sole feed to aquatic animals. Their remarkable capacity to fast growing in waste streams without competing arable land can also be greatly beneficial to aquaculture industry. Method: Research related to microalgae biotechnology is reviewed. The prospect of microalgal contribution to aquaculture has been summarised into several key themes, which are the advances in microalgae strains improvement, biorefinery-products for generation of renewable biofuels and aquaculture feed, and the algal bioremediate potential in aquaponics system. Results: Microalgae strains can be improved via bioengineering approach, targeting better traits for aquaculture. Furthermore, algal biorefinery derivatives show great potential to be fishmeal substitution with a number of environmental benefits, aligned with the biorefinery advance in biofuel industry. The cost and energy efficient microalgae cultivation module also provides a platform for aquaculture industry to strategically reduce hypereutrophic waste streams. In such a way, the ecological significances lie in alleviating the environmental pressure, offsetting the cost of algal production, and also generation of aquafeed functional inclusion with proven nutritional and immune benefits to the aquatic animals. Conclusion: With appropriate economic incentives, it is believed that the transition toward environmental friendly seafood production could be accelerated with concerted support of algal biotechnology, paving the way for aquaculture sustainable development.

Background: The current utilization of biomass to produce energy represents only about 2% of the annual production of biomass in the world. Recently, algae have received much attention due to the shortage of energy and mitigation of carbon dioxide, and are therefore considered as an alternative source of renewable energy. However, a major obstacle in the use of these biomasses is the highly complex composition of their cell walls. In algae, they are mainly composed of complex polysaccharides, like cellulose and hemicellulose, and proteins. All these macromolecules cannot be depolymerized by anaerobic bacteria for biofuel production. On the other hand, depolymerization of polysaccharides and proteins supplies nutrients for bacteria to produce bioethanol through fermentation or biogas by anaerobic digestion. To this aim, a pretreatment step is needed to break down the cell wall components, although the type of treatment depends on the specific composition of the adopted algae, as this can vary from species to species. Relevant studies have reported the efficiency of enzymatic pre-treatment to break up algae cell walls by combining the action of various cellulolytic enzymes. This strategy has been employed to enhance biofuel production and represents a promising alternative to other cell disruption methods. Results: This review provides an overview of the advantages of using algae for biofuel production and the current understanding of enzymatic pre-treatments in enhancing cellulose and hemicellulose degradation into fermentable monosaccharides. However, the performance of this approach depends on microalgae cell wall complexity. Conclusion: Given the diversity of algal cell wall composition, a thorough understanding of all possible enzymatic reactions one could exploit to depolymerize cell walls is a valid tool for efficient biofuel production.

Background: Algal cells produce neutral lipid when stressed and this can be used to generate biodiesel. Objective: Salt stressed cells of the model microalgal species Chlamydomonas reinhardtii were tested for their suitability to produce lipid for biodiesel. Methods: The starchless mutant of C. reinhardtii (CC-4325) was subjected to salt stress (0.1, 0.2 and 0.3 M NaCl) and transesterification and GC analysis were used to determine fatty acid methyl ester (FAME) content and profile. Results: Fatty acid profile was found to vary under salt stress conditions, with a clear distinction between 0.1 M NaCl, which the algae could tolerate, and the higher levels of NaCl (0.2 and 0.3 M), which caused cell death. Lipid content was increased under salt conditions, either through long-term exposure to 0.1 M NaCl, or short-term exposure to 0.2 and 0.3 M NaCl. Palmitic acid (C16:0) and linolenic acid (C18:3n3) were found to increase significantly at the higher salinities. Conclusion: Salt increase can act as a lipid trigger for C. reinhardtii.

Background: In order to establish safety and efficacy, generic medicines are required to prove bioequivalence with the innovator product while in case of Biosimilars (copy version innovator biologicals) requirements are product specific (case by case basis) and there is no common data requirement to establish the safety and efficacy. The challenge is to determine the nature of clinical and non-clinical studies required. Methods: The major causes of variability are its large size, complicated structure, stability issues, microheterogeneity involved and manufacturing process, etc. It is also difficult to draw a common regulatory pathway which covers all possible complex products. So, in this article we discuss the technicalities involved with this complex therapeutics (emphasizing on biosimilars) and look into regulatory frameworks for market authorization, keeping USFDA, EMA and ICH guidelines as standards. Results: Regulatory authorities have identified three main characteristics of a protein that must be considered during development i.e., 3D structures, post translational modifications (PTMs) and protein aggregation. Agencies generally consider the totality of the evidence to support a demonstration of biosimilarity, and recommend that sponsors should use a stepwise approach in the development of biosimilar products which may include a comparison of the proposed product and RBP with respect to Structure, Function, Animal Toxicity, Human Pharmacokinetics (PK) and Pharmacodynamics (PD), Clinical Immunogenicity, and Clinical Safety and effectiveness. Conclusion: There is also ambivalence about its future market considering the complicated development process involved. Its market growth has been alluring for pharmaceutical companies so far. An in-depth understanding of science involved and technologies available to explore may lead us to an affable regulatory pathway. In this review we put an effort to touch upon these aspects of biopharmaceuticals.

Background: The textile industry is one of the greatest generators of liquid effluent pollutants. Azo dyes are widely used (60-70%) in textile and becoming major source of environmental pollutants. Hence, in present study, an attempt is made, to study the role of microbial systems for bioremediation of a vinyl sulfone-based monoazo dye, Reactive Red 35 (RR35). Methods: RR35 dye degrading bacterium was isolated from the Common Effluent Treatment Plant and identified on the basis of a 16s rRNA sequence. The physicochemical parameters were optimized for maximum dye decolorization and degradation. Biodegradation of RR35 was confirmed by FTIR, HPTLC, and GC-MS analysis. Proficiency of the treatment was evaluated by performing cytogenotoxicity with Allium cepa and phytotoxicity with Triticum aestivum, Pennisetum glaucum, Phaseolus mungo and Vigna radiata. Results: The results revealed that isolated bacterium Enterococcus gallinarum can efficiently decolorize RR35 (300 mg l-1) with the rate of 76.81 mg l-1 h-1 at 40°C, pH 7 under static condition. Yeast extract was proved as an efficient substrate for decolorization of RR35. The isolate could efficiently decolorize RR35 at higher salinity (40 g l-1). E. gallinarum decolorized 1500 mg l-1 RR35 within 7 h during five repetitive spiking of RR35. After 96 ± 0.53% decolorization of RR35, 41 and 50% COD removal was observed under static and agitated condition, respectively; upon consequent incubation for 36 h. Induced activities of oxidoreductases proved their contribution in degradation of RR35. The proposed metabolic pathway for the degradation of RR35 is elucidated for the first time, which showed production of lower molecules weight compounds, 1-amino 3-(1- sulfonyl-2-sulfooxy ethane) benzene, and naphthalene 1, 7-diamine. Conclusion: E. gallinarum can degrade and detoxify RR35 dye very efficiently.