Joe Monahan, a principal planning engineer at the University of Pennsylvania, described a three-year pilot program of active air-quality monitoring and feedback control in a laboratory and a vivarium facility on campus.
Constant air volume change rates are traditionally built into the design of research and animal containment spaces to ensure sufficiently low levels of contaminants and particular matter. But this type of passive engineering approach is energy intensive, and Monahan presented the “need to go to a more active control system,” sampling the air in real-time and basing air exchange rates on the resulting measurements, rather than replacing clean air with clean air.
“No one ventilation rate is right all the time,” he said. If a spill occurs in a lab, for example, an active air sensing and ventilation system could adjust air flow accordingly.
Automatic air-sampling units installed as part of this project periodically route air samples to a centralized sensor suite that measures carbon monoxide, carbon dioxide, total volatile organic compounds, and particulates. Based on these readings, the system instructs the building control system whether or not to increase the air flow to the area sampled. To benefit from this capability the building must have a variable air flow system.
Monahan reported an energy cost savings of $15,000/year (from $95,000 down to $80,000, or 17%) for the research lab, with an ROI of 2.45 years, and a 42% drop in energy costs for the vivarium, with an ROI of 1.71 years.
Illustrating the benefits of a top-down corporate commitment to sustainability, Paul Lukitsch, worldwide energy manager for Millipore, described the company’s goals for reducing energy and water use from baseline measurements collected in 2006. He described a 15% drop in greenhouse gas (GHG) emissions, 15% reduction in electricity use, and a 22% decline in water use achieved by year-end 2009.
This would not have been possible without “a robust energy-management program,” said Lukitsch. “You need to invest in energy metrics.” Measure what you use, capture your energy costs and demand, perform intensive energy audits, identify fast ROI, low capital projects, execute scalable projects, and, above all else, “meter everything,” before and after making changes, he urged.
Take a multipronged approach and consider your options, he advised. Improving the efficiency of existing energy resources is likely to have a five times greater impact than switching to renewable sources such as solar energy.
“We are now starting to design our products with sustainability in mind,” added Lukitsch.
Demetri Petrides, Ph.D., president of Intelligen, producers of SchedulePro and SuperPro Designer software for process manufacturing, design, simulation, and scheduling, spoke on the impact of single-use systems on cleaning materials, cost of goods, and the environment.
He presented a case study involving a clinical manufacturing facility that produced 2 g/L of a mAb in four 2,000 L bioreactors over a 12-day period. Fixed (reusable, requiring CIP/SIP) bioreactors were replaced with disposables for product manufacturing, capture, purification, and storage (not including buffer preparation). The change reduced infrastructure needs from six equipment skids to three, water for infection (WFI) demand from a daily maximum of 35,000 L to 16,000 L, and a required WFI tank volume from 25,000 L to 15,000 L.
For a single production batch, Petrides reported declines in use of WFI by 51%, of caustic cleaning agents by 68%, of acids by 64%, and of clean steam by 52%. As a result, the cost of goods for antibody produced in disposables dropped to $352/gram, compared to $415/gram in fixed equipment.
The cost-saving benefits of disposables diminish as scale increases, noted Petrides. Whereas a manufacturer will “definitely save money for a 1,000–2,000 L scale facility,” by switching to disposable processing equipment, the turning point for savings is about 8,000 L, he said.
Replacing anion exchange column chromatography (AIEX) in the polishing step of a mAb product with Sartorius Stedim Biotech’s disposable Sartobind Q Membrane Adsorber technology allows for higher flow rates (0.1 CV/min for a column vs. 10–20 MV/min for the membrane), smaller devices (200 L resin column vs. 2 L membrane device), higher load density (up to 100 g/L of mAb on a column vs 10 kg/L on the membrane), and a 95% reduction in buffer consumption, according to case studies presented by Natalie Fraud, Ph.D., a senior process development scientist in purification technologies.
Use of a disposable membrane in place of AIEX chromatography for product polishing eliminated the need for column cleaning and yielded a savings of about 4% in the overall cost-of-goods and a savings of 3% in water usage.
Cleaning capacity was the largest bottleneck at one facility evaluated by Hyde Engineering + Consulting. Peter Watler, Ph.D., the company’s CTO, described a case study in which optimization of cleaning processes for one bioreactor resulted in 79% less water use, a 63% savings in cycle time, and 81% less CO2 production.
By combining multiple process vessels into a cleaning circuit, those figures declined further to 88%, 90%, and 90%, respectively, with an overall reduction from 7 to 2 cleaning cycles requiring 6 rather than 30 hours. This resulted in increased plant capacity, a savings of 12 million L of water per year, and annual cost-of-goods savings of $2.4 million.
Describing the current trend in bioprocessing toward smaller scale, reduced process volumes, and higher expression titers, Vincent Pizzi, global product marketing group leader at GE Healthcare, suggested that replacing reusable systems with single-use equipment from start to finish can provide the throughput needed to alleviate the growing pressure on downstream processes.
Replacing one 500 L stainless steel reactor with a single-use reactor over 40 production batches would save about 1,300 hours/year in CIP/SIP time and about $4,000 per batch on WFI.
Other talks at the conference focused on procurement and materials management to minimize inventories and create a centralized store of stock chemicals for better control of purchasing and disposal, solvent-sparing techniques in chromatography, and the use of biocatalysis to optimize chemical processes.
GEN is planning to hold its second “GreenBioPharma” meeting in Princeton, NJ, in 2011.