No abstract

SynopsisSeveral N-protected peptide amides, containing two aromatic residues spaced by one glycyl residue, have been enzymatically synthesized starting from P-Ar-OH and H-Gly-Ar-NH:! (P is the protecting group and Ar is the aromatic residue) and using wchymotrypsin as the catalyst for the coupling step. Reactions have been carried out in water solution, at room temperature, and afford yields ranging between 20 and 75% ca. This coupling reaction occurs in a much more restricted set of conditions than the hydrolysis reaction, e.g., only within a small pH range (ca. 6.5-7.5) and with particular buffering agents. The advantages and limitations of this type of reaction, compared with conventional coupling procedures, are discussed.

No abstract

No abstract

S u m m a r yThe growth behavior of Chaeromium cellulolyticum, a new cellulolytic fungus, has been examined in slurry fermentation systems using various chemically pretreated sawdusts from hardwoods as substrates. Both acid-and alkali-pretreatment methods were used and the fermentation media included the spent pretreatment liquor in an attempt to concurrently maximize substrate utilization and minimize the biological oxygen demand (BOD) level in the process effluent. Diauxic growth patterns were found in the three cases studied, suggesting an initial utilization of soluble hemicellulose sugars followed by utilization of the insoluble cellulose. This behavior pattern was supported by separate growth experiments using the major sugars of hemicellulose as carbon sources. The organism was found to be a good convertor of both cellulose and hemicelluloses into single cell protein (SCP). In terms of rate and extent of protein production in the insoluble biomass product, acid pretreatment appears to be better than alkali pretreatment if the product is intended as ruminant feed.