Current perspectives on biosimilars

In this work, an overview of the biosimilars market, pipeline and industry targets is discussed. Biosimilars typically have a shorter timeline for approval (8 years) compared to 12 years for innovator drugs and the development cost can be 10–20% of the innovator drug. The biosimilar pipeline is reviewed as well as the quality management system (QMS) that is needed to generate traceable, trackable data sets. One difference between developing a biosimilar compared to an originator is that a broader analytical foundation is required for biosimilars and advances made in developing analytical similarity to characterize these products are discussed. An example is presented on the decisions and considerations explored in the development of a biosimilar and includes identification of the best process parameters and methods based on cost, time, and titer. Finally factors to consider in the manufacture of a biosimilar and approaches used to achieve the target-directed development of a biosimilar are discussed.

     

Effect of pretreatment chemicals on xylose fermentation by Pichia stipitis

Pretreatment of biomass with dilute H₂SO₄ results in residual acid which is neutralized with alkalis such as Ca(OH)₂, NaOH and NH₄OH. The salt produced after neutralization has an effect on the fermentation of Pichia stipitis. Synthetic media of xylose (60 g total sugar/l) was fermented to ethanol in the presence and absence of the salts using P. stipitis CBS 6054. CaSO₄ enhanced growth and xylitol production, but produced the lowest ethanol concentration and yield after 140 h. Na₂SO₄ inhibited xylitol production, slightly enhanced growth towards the end of fermentation but had no significant effect on xylose consumption and ethanol concentration. (NH₄)₂SO₄ inhibited growth, had no effect on xylitol production, and enhanced xylose consumption and ethanol production.     

Cellulosic ethanol production using the naturally occurring xylose-fermenting yeast, Pichia stipitis

Rising crude oil prices and environmental concerns have renewed interest in renewable energy. Cellulosic ethanol promises to deliver a renewable fuel from non-food feedstocks. One technical challenge producing cellulosic ethanol economically is a robust organism to utilize the different sugars present in cellulosic biomass. Unlike starch where glucose is the only sugar present, cellulosic biomass has other sugars such as xylose and arabinose, usually called C5 sugars. This review examines the most promising naturally occurring C5 fermenting organism, Pichia stipitis. In this work, the properties that make P. stipitis unique from other organisms, its physiology and fermentation results on lignocellulosic substrates have been reviewed. P. stipitis can produce 41 g ethanol/l with a potential to cleanup some of the most concentrated toxins. These results coupled with the less stringent nutritional requirements, great resistance to contamination and its thick cell walls makes P. stipitis a viable organism for scale-up. However, P. stipitis has a slower sugar consumption rate compared to Saccharomyces cerevisiae and requires microaerophilic condition for ethanol production. Finally, future studies to enhance fermentation capabilities of this yeast have been discussed.     

Lime treatment of shrimp head waste for the generation of highly digestible animal feed

In addition to approximately 20% ash, shrimp processing by-products contain 64% protein and chitin, both of which can be used to generate several valuable products. Chitin and chitosan production is currently based on several crustacean wastes, and at the present time the protein fraction is not being used. This paper describes the thermo-chemical treatment of shrimp processing wastes with lime to generate a protein-rich material with a well-balanced amino acid content that can be used as a monogastric animal feed supplement. The residual solid, rich in calcium carbonate and chitin, can still be used to generate chitin and chitosan through well-established processes.     

Conversion of municipal solid waste to carboxylic acids using a mixed culture of mesophilic microorganisms

Waste biomass was anaerobically converted to carboxylate salts by using a mixed culture of acid-forming microorganisms. Municipal solid waste (MSW) was the energy source (carbohydrates) and sewage sludge (SS) was the nutrient source (minerals, metals, and vitamins). Four fermentors were arranged in series and solids and liquids were transferred countercurrently in opposite directions, which allows both high conversions and high product concentrations. Fresh biomass was added to Fermentor 1 (highest carboxylic acid concentration) and fresh media was added to Fermentor 4 (most digested biomass). All fermentations were performed at 40 degrees C. Calcium carbonate was added to the fermentors to neutralize the acids to their corresponding carboxylate salts. Iodoform was used to inhibit methane production and urea was added as a nitrogen source. Product concentrations were up to 25 g/L, with productivities up to 1.4 g total acid/(L liquid d). Mass balances with closure between 93% and 105% were obtained for all systems. Continuum particle distribution modeling (CPDM) was applied to correlate batch fermentation data to countercurrent fermentation data and predict product concentration over a wide range of solids loading rates and residence times. CPDM for lime-treated MSW/SS fermentation system predicted the experimental total acid concentration and conversion within 4% and 16% respectively.     

Lime treatment of keratinous materials for the generation of highly digestible animal feed: 2. Animal hair

Air-dried cow hair was treated using Ca(OH)(2) (insoluble in water but dissolved during reaction) at 100 degrees C. To obtain a liquid product rich in amino acids, a well-insulated, stirred reactor was used to perform the hydrolysis process for different time periods. High lime loadings and a long treatment period convert 70% of cow hair to soluble amino acids and polypeptides. Protein solubilization varies with lime loading especially for the long-term treatment (t>12h) showing that the hydroxyl group is required as a catalyst for the hydrolysis reaction and that lime is consumed during the process; as a consequence lower lime loading generate lower conversions. A very perceptible ammonia odor in the soluble product suggests amino acid degradation. Arginine, threonine, and serine are the more susceptible amino acids under alkaline hydrolysis. The amino acid composition of the solubilized product compares poorly with the essential amino acid requirements for various monogastric domestic animals, but it has value as ruminant feed.     

Isoform-specific O-glycosylation by murine UDP-GalNAc:polypeptide N- acetylgalactosaminyltransferase-T3, in vivo

Multiple isoforms of UDP-GalNAc:polypeptide N-acetylgalactosaminyl- transferase (ppGaNTase) have been cloned and expressed from a variety of organisms. In general, these isoforms display different patterns of tissue-specific expression, but exhibit overlapping substrate specificities, in vitro . A peptide substrate, derived from the sequence of the V3 loop of the HIV gp120 protein (HIV peptide), has previously been shown to be glycosylated in vitro exclusively by the ppGaNTase-T3 (Bennett et al. , 1996). To determine if this isoform- specificity is maintained in vivo , we have examined the glycosylation of this substrate when it is expressed as a reporter peptide (rHIV) in a cell background (COS7 cells) which lacks detectable levels of the ppGaNTase-T3. Glycosylation of rHIV was greatly increased by coexpression of a recombinant ppGaNTase-T3. Overexpression of ppGaNTase- T1 yielded only partial glycosylation of the reporter. We have also determined that the introduction of a proline residue at the +3 position flanking the potential glycosylation site eliminated ppGaNTase- T3 selectivity toward rHIV observed both in vivo and in vitro .      

Lime treatment of keratinous materials for the generation of highly digestible animal feed: 1. Chicken feathers

Chicken feather keratin was treated with lime (calcium hydroxide) to obtain a liquid product rich in amino acids and polypeptides that can be used as an animal feed supplement. The effect of treatment conditions and the properties of the soluble keratin were studied. At high temperatures (150 degrees C), 80% of feather keratin was solubilized within 25 min, whereas a relatively longer reaction time (300 min) is needed at moderate temperatures (100 degrees C). After 3h of hydrolysis at 150 degrees C, 95% of feather keratin was digested. For the recommended conditions (100 degrees C, 300 min, and 0.1g Ca(OH)(2)/g dry feather), after lime treatment, about 54% of calcium can be recovered by carbonating. In rumen fluid, ammonia production from soluble keratin was similar to that of soybean and cottonseed meals and was greatly less than that of urea, indicating that no ammonia toxicity will result from cattle being fed soluble keratin.     

Fixed-bed fermentation of rice straw and chicken manure using a mixed culture of marine mesophilic microorganisms

A mixture of rice straw (80%) and chicken manure (20%) was pretreated and fermented to carboxylic acids by using a mixed culture of marine mesophilic microorganisms. Two sets of four fermentors, built from PVC pipes, were used for both biomass pretreatment and fermentation. Four 1L fermentors (F1-F4) were arranged in series, where liquid fermentation products were transferred from one fermentor to the other, to form a train. A liquid volume of 10mL and 15mL were transferred every four days for Trains A and B, respectively. The maximum total acid concentration for F1 in Train A was 34.2g/L and the maximum acid concentration in F2-F4 was approximately 44g/L. The maximum total acid concentration in F1 in Train B was 30.5g/L and the maximum acid concentration in F2-F4 was approximately 48g/L. The conversion in each of the fermentors in Train A varied from 0.821 to 0.879g VS digested/g VS fed and the yield was in the range 0.489-0.609g total acids/g VS fed. The conversion and yield in Train B were 0.741-0.914g VS digested/g VS fed and 0.563-0.669g total acids/g VS fed, respectively. The continuum particle distribution model (CPDM) predicted acid concentrations and retention times in the fixed-bed fermentation system with R(2) of 0.67-0.84 in Trains A and B.