Paper360 - July/August 2013 - (Page 26)

TECHLINK ENZYMES Next Generation Enzymes for the Paper and Pulp Industry Enzymes have long been part of the paper making process, but next generation enzymes use less energy, increase efficiency and operate at wider pH ranges MARK EMALFARB N ext generation enzymes use genetic engineering to optimize the action of enzymes. The first step is the search for a gene that will produce the desired enzyme. High speed robots scan for genes using an assay that indicates the presence of the desired gene. The process is known as High Throughput Robotic Screening or HTRS (Figure 1). Once a desired gene is located, it is extracted and inserted into a host organism to reproduce millions of copies of the cell containing the gene. Host organisms are single cell organisms that with genetic manipulation can be turned into little enzyme/protein factories. There are a variety of host organisms including Yeast, Chinese Hamster Ovaries, Viral Vectors, and Fungi such as C1—a proprietary fungal expression system from Dyadic. Hosts are where research companies differ in their approach. While some companies extract the desired gene and insert it into a test host organism and produce laboratory quantities for further examination, others work directly with the commercialization host organism to ensure that the desired gene Figure 1. Vial P shows a positive assay. 26 Paper360º JULY/AUGUST 2013 can be expressed on a commercial scale. This is an important difference because often the products produced by test hosts require further manipulation to make them suitable for the commercial host. While working with the host organisms, genes that inhibit the production of the desired protein or enzyme are removed to optimize the production of the desired product. Once a host strain is produced in sufficient quantities, it is inserted into large industrial fermentation vessels to produce the desired enzyme. NEXT GENERATION ENZYMES AND PULP: ENDOGLUCANASE Wood pulp fibers in a raw state contain both crystalline fibrils and less ordered cellulose structures on the surface. Endoglucanases help strip these fibrils from the surface of the wood and attack the less ordered structures that are to some extent degraded. Mild to moderate beating increases fibrillation on the fiber surface increasing fiber-to-fiber interactions and yielding a stronger pulp (Figure 2). An improved next-generation endoglucanase interacts with cellulose in such a way that it facilitates degradation to the fiber wall structure allowing the pulp to be mechanically refined using lower energy input. The endoglucanase is also capable of hydrolyzing the small fibrils, or fines, that are released from the fiber wall without consuming the more ordered cellulose structures composing the bulk of the fiber. This effect can improve drainage when pulp reaches the paper machine, which may have a positive effect on productivity due to potential increases in paper machine speed. The next-generation endoglucanase is also highly flexible—operating within wider temperature and pH ranges making it more adaptable in existing pulp mill processes. Dosage also is highly flexible yielding higher tensile strength than other cellulases (see Fig. 3). Typical cellulase enzymes often must be confined to a narrow dosage range or reaction time as overdose effects might occur if applied improperly due to excess degradation of the fiber wall prior to refining. Following initial screening and industrial fermentation scale up, next generation enzymes go through extensive laboratory and mill trials to determine optimal dosage and effect under process-specific conditions. MILL TRIAL RESULTS Trial 1: Multi-liner board, Southeast Asia, 500 TPD capacity. The endoglucanase product was applied to the bottom layer of a multi-liner board at dosages ranging from 90-160 g/mT. As a result of successful treatment, machine speed was increased by 9 percent which in turn increased production by 44 TPD. Trial 2: Six-ply coated and uncoated paper, 400 TPD capacity. The multi-ply paper was composed of a bleached eucalyptus top layer, an ONP bottom layer, and recycled

Table of Contents for the Digital Edition of Paper360 - July/August 2013

Over the Wire . . . News Summary
Ready for Print 2.0?
Eldorado Brasil Begins Operations in the Pulp Industry
Newark’s Frank Papa on Leadership and Innovation
Tissue Mill Dewaters Pulp with Innovative Disc Filter
TAPPI Journal Summaries
Next Generation Enzymes for the Paper and Pulp Industry
The Best Resources for Your Best Resources
Consolidation Watch
Association News
What’s New on

Paper360 - July/August 2013