To compare the efficiency of various whole cell immobilization techniques for the production of gluconic acid by Aspergillus niger were investigated using potassium ferrocyanide-treated cane molasses as the substrate. The techniques followed were: (1) Calcium alginate entrapment, (2) cross-linking with glutaraldehyde after cell permeabilization with (a) acetone, (b) toluene and (c) isopropanol and (3) development of granular catalyst. A comparative analysis of yield has revealed that calcium alginate entrapment was the most suitable technique as it had given the maximum product yield (0.40 g gluconic acid/g total reducing sugar supplied). The properties of immobilized A.niger in sodium alginate gel have been thoroughly investigated and compared with those of free cells under most suitable conditions of fermentation. © 1994 Springer-Verlag.

T Panda

Department Of Chemical Engineering

D. Subba Rao

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Comparative analysis of different whole cell immobilized aspergillus niger catalysts for gluconic acid fermentation using pretreated cane molasses

Bioprocess Engineering

An attempt to produce ethanol from a cellulosic substrate by a single-stage process using intergeneric hybrids obtained from Trichoderma reesei QM 9414 and Saccharomyces cerevisiae NCIM 3288 fusants is described. Two hundred one fused strains were isolated using two different combinations of hybridization, followed by polyethylene glycol treatment of protoplasts derived from parent and mutant strains. Some fusants were either diploids or heterokaryons, as verified by a protoplast fused system obtained by auxotrophic mutants derived from T. reesei QM 9414 and S. cerevisiae NCIM 3288. Of the 201 fusants, 170 were found to be relatively stable. Two fusants (M14 and M62) showed the highest synthesis of ethanol from filter paper cellulose, producing 0.0149 and 0.0191 g l-1, respectively. © 1994.

Enzyme and Microbial Technology

Intergeneric hybridization of Trichoderma reesei QM9414 and Saccharomyces cerevisiae NCIM 3288 by protoplast fusion

Gluconic acid fermentation by Aspergillus niger has been investigated using untreated and treated Indian cane molasses. The yield of gluconic acid was found to be reduced using an untreated molasses medium compared to a defined medium. Hence, molasses was subjected to various pretreatment techniques. Pretreatment reduced the levels of various cations and anions. As the synthesis of gluconic acid has been observed to be influenced more by cations than anions, the effect of various metal ions, viz., copper, iron, zinc, manganese, calcium, and magnesium on the yield of gluconic acid has been critically examined in both untreated and treated cane molasses. These results have been compared with a defined medium. The yield of gluconic acid was influenced more by a combination of metal ions rather than individual ions. Potassium ferrocyanide treatment gave the most promising results compared to other treatment techniques. © 1994 Springer-Verlag.

Critical analysis of the effect of metal ions on gluconic acid production by Aspergillus niger using a treated Indian cane molasses

Sodium gluconate and calcium gluconate methods are important techniques available for gluconic acid fermentation. The comparative analysis of these fermentations has been addressed using Aspergillus niger. The techniques are equally influenced by the spores age in slant growth, inoculum level in germination and production media, different levels of Fe, Cu, Zn and Mn. Sodium gluconate method is promising with respect to lesser time for slant age (3 d) and lesser time of fermentation (6 d) compared to the calcium gluconate method (slant age - 6 d, and time of fermentation - 7 d). © 1993 Springer-Verlag.

Comparative analysis of calcium gluconate and sodium gluconate techniques for the production of gluconic acid by Aspergillus niger

To obtain a catalyst with good mechanical stress stability and other operational characteristics, cross-linked aggregates of whole Escherichia coli containing penicillin amidase were reinforced with surface modified precipitated silica and chitosan. The immobilized cells plus mixed fillers possess better performance characteristics i.e. higher stability at 4°C and 30°C, least protein leaching capacity and good settling characteristics. Most suitable conditions to prepare catalyst with mixed fillers were: chitosan, 0.3: silica, 0.2 g/g d.wt cell; and minimum moisture content in catalyst, 30% (w/w). © 1991 Chapman & Hall.

Journal	Data powered by TypesetBioprocess Engineering
Publisher	Data powered by TypesetSpringer-Verlag
ISSN	0178515X
Open Access	No