Development of the cephalosporin C fermentation taking into account the instability of cephalosporin C
JJ Usher, MA Lewis, DW Hughes, BJ Compton - Biotechnology letters, 1988 - Springer
Cephalosporin C undergoes chemical hydrolysis during fermentation at 25° C at a rate of
0.48% per hour to give increasing amounts of 2-(D-4-amino-4-carboxybutyl) thiazole-4-
carboxylic acid (compound X). Although the cephalosporin C titer in a fermentation levels off
at 160–170h, the total of C+ X rises almost linearly up to 200h. Cells, therefore,
biosynthesize cephalosporin C at an almost constant rate up to 200h. This instability greatly
influences attempts to improve the cephalosporin strain by genetic manipulation, or the …
0.48% per hour to give increasing amounts of 2-(D-4-amino-4-carboxybutyl) thiazole-4-
carboxylic acid (compound X). Although the cephalosporin C titer in a fermentation levels off
at 160–170h, the total of C+ X rises almost linearly up to 200h. Cells, therefore,
biosynthesize cephalosporin C at an almost constant rate up to 200h. This instability greatly
influences attempts to improve the cephalosporin strain by genetic manipulation, or the …
Exploring problems of self‐directed learning within practice and discourse
R Usher, R Johnston - Studies in Continuing Education, 1988 - Taylor & Francis
Self‐directed learning is an important feature in using experiential approaches with adult
students. It is both part of a theorisation and the basis of certain kinds of practices which
together form a 'discourse'of self‐directed learning. The paper critically examines the
general characteristics of this discourse and considers the consequences of the
assumptions made about adult learning and teaching. Case studies of practice involving
experiential teaching approaches with two different groups of adult students are then …
students. It is both part of a theorisation and the basis of certain kinds of practices which
together form a 'discourse'of self‐directed learning. The paper critically examines the
general characteristics of this discourse and considers the consequences of the
assumptions made about adult learning and teaching. Case studies of practice involving
experiential teaching approaches with two different groups of adult students are then …