Method for Inclusion Bodies Production via E. coli Host System: rGCSF as Model Biotherapeutic Protein.

Escherichia coli is an industrial-relevant microbial host system, which is highly preferred for the large-scale production of recombinant biotherapeutics. Overexpression of these recombinant biotherapeutics in the E. coli system often results in the formation of insoluble protein aggregates termed as inclusion bodies (IBs). The yield and quality of IBs are affected by a spectrum of parameters like temperature, optical density, medium composition, induction time, and amount of inducer. Here, we present a protocol for the formation and processing of IBs for production of recombinant human granulocytes colony-stimulating factor (rGCSF).

Real time light intensity based carbon dioxide feeding for high cell-density microalgae cultivation and biodiesel production in a bubble column photobioreactor under outdoor natural sunlight.

Outdoor high cell-density microalgae cultivation is highly challenging due to unavailability of appropriate CO2 feeding strategy under diurnal sunlight intensities. Hence, a novel real time light based CO2 feeding strategy was firstly developed under diurnal simulated sunlight (LED) to test on Chlorella sp. in a 10 L scale bubble column photobioreactor. The strategy yielded a biomass titer of 5.12 g L-1 under simulated sunlight, far higher than existing biomass-density and pH-control based CO2 feeding strategies. In outdoor culturing, the proposed feeding strategy yielded high biomass titers of 6.8 and 9.0 g L-1 in growth-phase of two-stage and single-stage lipid induction studies respectively with same biomass productivity of 0.8 g L-1 day-1. Subsequently, two-stage lipid induction strategy of 6.8 g L-1 titer yielded biodiesel productivity of 120 g L-1 day-1, whereas single-stage strategy of 9.0 g L-1 titer was unable to induce lipid. Moreover, specific light availability affects the lipid production.

Production of biodiesel by autotrophic Chlorella pyrenoidosa in a sintered disc lab scale bubble column photobioreactor under natural sunlight.

The main focus of the work is to study Chlorella pyrenoidosa mediated photoautotrophic production of lipid in a bubble column photobioreactor using CO2 as carbon source under natural diurnal outdoor sunlight. The limiting and inhibiting concentrations of CO2 in sparging gas, nitrogen inhibition, reversibility of the CO2 inhibition on growth, and lipid production have been investigated under natural sunlight. A process model coupled with light distribution inside the culture has been developed considering different concentration of dissolved CO2 and urea, repression of nitrogen on lipid production under natural sunlight diurnal in nature in a bubble column reactor. The biomass titer of 4.6 g/L with 10% CO2 has been achieved within 5 days of culture under sunlight. A two stage photoautotrophic lipid production strategy in a sintered disc bubble column photobioreactor under natural sunlight has been developed. 30% (w/w-DCW) lipid within 5 days of lipid induction period has been achieved. The biomass productivity of 0.91 ± 0.01 gm/L/day in growth period with sufficient urea and lipid productivity of 410 ± 12 mg/L/day in last 2 days of urea starvation period have been achieved in outdoor photoautotrophic cultivation under natural sunlight using CO2 as carbon source.

Concomitant production of fatty acid methyl ester (biodiesel) and exopolysaccharides using efficient harvesting technology in flat panel photobioreactor with special sparging system via Scenedesmus abundans.

Current study focusses on the concomitant production of fatty acid methyl ester (FAME, biodiesel) and exopolysaccharides (EPS) from Scenedesmus abundans cell factory in flat panel photobioreactor using cost effective harvesting strategy. Parallel mini and medium scale flat panel photobioreactors (PBRs) with special gas sparging system enabling high gas to liquid mass transfer and efficient mixing were designed. Biomass titer of 6.9 g/l with overall biomass productivity of 1.2 g/l/day was achieved with constant high light intensity of 2162 µE/m2/s in growth phase (134 h) using optimum nutrient concentration. FAME concentration of 1.53 g/l was achieved after 15 days of nitrogen deprivation condition with productivity of 67 mg/l/day. The EPS production of 236 mg/l with a yield of 37 mg/g biomass was achieved. The strain proved its capability to produce multiproducts simultaneously in a single stage PBR by natural autoflocculation harvesting technology.

Designing a CO2 supply strategy for microalgal biodiesel production under diurnal light in a cylindrical-membrane photobioreactor.

A cylindrical membrane photobioreactor with high CO2 mass transfer coefficient was designed and installed under customized unidirectional lighting. Combinatorial effect of light and CO2 on the growth of Chlorella sp. FC2 IITG was studied and an optimal CO2 supply without pH control strategy was developed under diurnal light similar to sunlight (17-2000-17 µE m-2 s-1). Unprecedentedly, broad range of saturated light levels (700-1500 µE m-2 s-1), reversible photoinhibition, no pH control requirement and dark-phase growth were noticed altogether in the strain. Under diurnal light, final biomass titer of 5.79 g L-1 and overall biomass productivity of 1.29 g L-1 day-1 were observed. The results were similar to optimal light (1130 µE m-2 s-1) and CO2 (2%) conditions. Subsequently, a highest FAME productivity of 265 mg L-1 day-1 was observed in last two days of lipid induction phase.