The objective of this study is to examine large-scale spatial patterns of tree growth and climatic variation and to investigate the possible role of climate in determining tree growth patterns over space. This study represents one of the first uses of geostatistical methods to extract information about the spatial variation of climate from tree rings in western North America. It is also one of the first uses of data in spatial series to study the relationships of spatial variations between climate and tree growth. Geostatistics analyzes the spatial structure of the variables by assuming that adjoining data are correlated with each other over space and that the particular relationship expressing the extent of spatial correlation can be analytically and statistically captured in a function. It is applied to both June Palmer Drought Severity Index (PDSI) and ring-width index data from western North America. One basic assumption of applying geostatistics in this study is that the spatially uncorrelated small-scale variations are insignificant and represent background noise in large-scale dendroclimatic studies. The statistical relationships between the spatial variations of June PDSI and ring-width index are studied by simple scatter diagrams and correlation analysis. This is done in terms of yearly variations and variations of spatial patterns. Both of them support the contention that the large-scale spatial variations in ring-width index data can be used to infer the spatial variations of climate variables. Based upon the results of this research it can be concluded that geostatistics is a viable method to characterize the spatially correlated variations in dendroclimatology. By applying geostatistics to data sets, information about the spatial variations of climate contained in tree-ring data are enhanced, and the large-scale variations of climate are emphasized. The analysis of yearly relationships over space is particularly useful for identifying statistical relationships between climate and tree growth in a geographic region. The main factors of climate controlling ring-width index are identified as well as the less frequent limiting events. Once the statistical relationships are validated, they can be used to infer the spatial variations of past climate from variations in tree-ring index.

No description available.

No description available.

Includes list of publications produced during the period of candidature / Includes bibliographical references (leaves 254-274) / xiv, 274 leaves : ill. (col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 2003

The aims of this study were to investigate the P solubilising activity of Penicillium radicum and identify other possible mechanisms of plant growth promotion that were not related to P solubilisation. The plant chosen for the studies was wheat, the largest cereal commodity produced by Australian agriculture. Given the large area that is planted annually to wheat, this crop represents a large potential market for P. radicum-based inoculants. However, it is unlikely that P. radicum will be effective in all wheat growing regions and all environmental conditions seen in these areas. Research on the modes of action may help to identify the conditions where P. radicum has a good chance of being effective. The P solubilising activity of P. radicum was assessed by examining the amount of P released from rock phosphate (RP) in-vitro. The effectiveness of P. radicum to solubilise RP was compared to that of another P solubilising fungus, the isolate P. bilaiae RS7B-SD1. Both fungi were cultured in a liquid medium that contained either NO₃⁻ or NH ₄⁺ as the sole source of N. Changes in culture pH, soluble P and gluconic acid concentration were determined for both fungi in a 168 hour incubation in both buffered (100 mM Tris-HCl pH 7.8) and non-buffered medium. For P. radicum, the maximum concentration of soluble P was 6.8 fold higher in the presence of NH₄⁺ compared to NO₃⁻. In contrast, for P. bilaiae RS7B-SD1 the highest concentration of soluble P measured in the fungal culture was not significantly affected by N-source. In buffered medium, P. radicum did not appear to solubilise RP and levels of soluble P were generally <1 mg L⁻¹. In contrast, the RP solubilising activity of P. bilaiae RS7B-SD1 was not affected by buffering. Increased RP solubilisation with NH₄⁺ as the N source and lack of RP solubilisation in buffered medium suggested that acidification was the main mechanism of P solubilisation by P. radicum. RP solubilisation by P. bilaiae RS7B-SD1 was similar over the range of culture conditions tested and mechanisms of RP solubilisation are likely to be a combination of mechanisms that relate to both acidification and the production of organic anions. The effect of inoculation with P. radicum on plant growth and P nutrition was studied under glasshouse conditions using a sand culture assay that supplied defined sources of P. The plant growth and P response to P. radicum inoculation were determined in two separate experiments. In Experiment 1, plants were grown to pre-heading stage and supplied with either dibasic calcium phosphate (Ca-P), crystalline iron phosphate (Fe-P), rock phosphate (RP) or phytate (Pₒ) as the source of P. In Experiment 2, plants were harvested after 8 weeks and supplied with either NO₃⁻ or NH₄⁺ as the sole source of N and the P sources were either Ca-P or RP. In Experiment 1, the plant P response (defined as higher shoot P concentration and P uptake) to inoculation was dependent on the P source. The greatest plant P response to inoculation was observed for Ca-P and no significant P response was measured in plants that were supplied with Fe-P, RP or Pₒ. In pots that supplied Fe-P as the P source, there was an increase in shoot dry matter in response to P. radicum inoculation but this occurred without a concomitant plant P response. In Experiment 2, the plant P response to inoculation was dependent on the N source. In the presence of NH₄⁺, P. radicum significantly increased the availability of P sources RP and Ca-P. While there was no significant plant P response under NO₃⁻ supply, there was a significant increase in dry matter production due to P. radicum inoculation. When the data of Experiments 1 & 2 are taken together, results suggest that P. radicum possesses at least two mechanisms of plant growth promotion, (1) P solubilisation and (2) general growth promotion that is independent of P solubilisation. In agreement with P solubilisation in solution cultures, the P solubilisation mechanism of P. radicum in sand culture required NH₄⁺. The ability of P. radicum to increase plant growth independently of a plant P response gave further evidence of general growth promoting abilities of the fungus. While sand culture is a useful tool to elucidate the fungal mechanisms of plant growth promotion, this approach cannot fully reflect the complexity of the rhizosphere in non-sterile soil. Hence, a subsequent experiment was done to determine the effect of P. radicum on plant growth and P nutrition in a number of field soils. The P solubilising activity of P. radicum was determined in four Australian field soils using isotopic dilution. Three soils were chosen on the basis of their chemistry of P retention: (1) Minnipa soil from South Australia was chosen due to P retention associated with the highly alkaline calcareous nature of this soil; (2) Innisfail Queensland, in this soil P retention was dominated by reaction with Fe oxides; and (3) Mt Schank South Australia, a volcanic soil where P retention was predominantly associated with Al oxides. The fourth soil, from Mingenew Western Australia, was chosen due to previous reports that P. radicum inoculation increased the yield of field grown wheat (Bio-Care Technology, unpublished data). The four field soils were each labelled with KH₂ ³²PO₄ and the specific activity (³²P) of the wheat seedling tissue was measured after four weeks growth. When the data was averaged across all four soil types, inoculation with P. radicum caused a significant 11.7% increase in the shoot dry weight of these seedlings. However, P. radicum did not cause any consistent significant difference in the specific activity (³²P) of plants when compared to uninoculated control plants. These results suggested that P. radicum did not have a strong ability to solubilise P from the test soils, and mechanisms other than P solubilisation were in operation to stimulate plant growth. The production of plant growth regulators (PGR) was considered as a mechanism of plant growth promotion not related to P solubilisation. To further explore the hypothesis that the production of PGR acts as a mechanism of plant growth promotion, the ability of P. radicum to produce the auxin, indole-3-acetic acid (IAA) was investigated. Examination with thin-layer chromatography and the Avena coleoptile straight growth assay indicated that fractions of P. radicum culture medium with chemical characteristics similar to IAA (i.e. similar reaction to the Salkowski reagent and Rf as IAA) also possessed auxin-like activity. Using competitive enzyme linked immunosorbent assay (ELISA) it was found that in liquid culture amended with the precursor tryptophan, P. radicum produced IAA at concentrations up to 0.406 µM. These studies show that P. radicum can produce IAA under laboratory culture conditions. To determine the significance of IAA as a mechanism of plant growth promotion, further studies need to link effects on plant growth and development to the production of IAA by P. radicum. The ability of P. radicum to antagonise root pathogens and control root disease was considered as a further mechanism of growth promotion. Under in-vitro conditions, P. radicum produced hyphal growth patterns and enzymes (protease, β-1,3- and β-1,4-glucanase activity) that were indicative of hyperparasitism. Hyperparasitic growth was seen as hyphal coiling and branching of P. radicum against host hyphae of Rhizoctonia solani, Fusarium pseudograminearum and Pythium irregulare when these soilborne pathogens were studied in dual culture with P. radicum. The effect of P. radicum on the fungal root disease severity of take-all was studied using a seedling bioassay under glasshouse conditions. The ability of P. radicum to suppress take-all disease appeared to be related to the timing of P. radicum infection of wheat seedling roots and placement of the Ggt inoculum in relation to the roots. Compared to soils where Ggt inoculum was only distributed at distances >1 cm below the seed, uniform mixing of the Ggt inoculum throughout the soil negated the beneficial effect of P. radicum on plant growth and its ability to reduce take-all root lesion size. Conversely, early infection of wheat roots by P. radicum gave wheat seedlings some protection against take-all disease. Where treatment with P. radicum was effective, increasing the inoculum dose significantly reduced take-all lesion size. While P. radicum exhibited antagonism towards F. pseudograminearum, Py. irregulare, Bipolaris sorokiniana and R. solani cereal root pathogens in-vitro, further studies under non-sterile soil conditions are needed to evaluate the potential for P. radicum to reduce root disease caused by these fungi. In conclusion, it is unlikely that one single mechanism explains the beneficial effect of P. radicum on wheat growth. In-vitro studies showed that P. radicum has a number of attributes that could function as mechanisms of plant growth promotion. These attributes were, (1) P solubilisation, (2) production of IAA and (3) the ability to antagonise soilborne pathogens in-vitro and reduce the lesion size of the take-all disease in a seedling bioassay. Sand culture assays revealed that at least two plant growth mechanisms were in operation, (1) P solubilisation and (2) a general growth promotion mechanism that was independent of P solubilisation. In agreement with Whitelaw et al. (1999), the P solubilisation mechanism of P. radicum operates via an acidification mechanism. The effectiveness of this mechanism may be limited by the availability of NH₄⁺ in the rhizosphere. Since NH₄⁺ appears to be required for P solubilisation there may exist an interaction between P. radicum and ammoniacal fertilisers. This will have implications for its effectiveness in the field. In-vitro studies suggest that the general mechanism of growth promotion may be related to the production of PGRs such as IAA. In this aspect the known colonisation of the interior of wheat roots by P. radicum would ensure that IAA produced by the fungus is taken up by the root cell and less subject to chemical degradation and/or degradation by other soil microorganisms. Further studies are required to identify the effect of IAA production on plant growth and the effect of P. radicum inoculation on root disease severity in non-sterile soil. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1165226 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2004.

The aims of this study were to investigate the P solubilising activity of Penicillium radicum and identify other possible mechanisms of plant growth promotion that were not related to P solubilisation. The plant chosen for the studies was wheat, the largest cereal commodity produced by Australian agriculture. Given the large area that is planted annually to wheat, this crop represents a large potential market for P. radicum-based inoculants. However, it is unlikely that P. radicum will be effective in all wheat growing regions and all environmental conditions seen in these areas. Research on the modes of action may help to identify the conditions where P. radicum has a good chance of being effective. The P solubilising activity of P. radicum was assessed by examining the amount of P released from rock phosphate (RP) in-vitro. The effectiveness of P. radicum to solubilise RP was compared to that of another P solubilising fungus, the isolate P. bilaiae RS7B-SD1. Both fungi were cultured in a liquid medium that contained either NO₃⁻ or NH ₄⁺ as the sole source of N. Changes in culture pH, soluble P and gluconic acid concentration were determined for both fungi in a 168 hour incubation in both buffered (100 mM Tris-HCl pH 7.8) and non-buffered medium. For P. radicum, the maximum concentration of soluble P was 6.8 fold higher in the presence of NH₄⁺ compared to NO₃⁻. In contrast, for P. bilaiae RS7B-SD1 the highest concentration of soluble P measured in the fungal culture was not significantly affected by N-source. In buffered medium, P. radicum did not appear to solubilise RP and levels of soluble P were generally <1 mg L⁻¹. In contrast, the RP solubilising activity of P. bilaiae RS7B-SD1 was not affected by buffering. Increased RP solubilisation with NH₄⁺ as the N source and lack of RP solubilisation in buffered medium suggested that acidification was the main mechanism of P solubilisation by P. radicum. RP solubilisation by P. bilaiae RS7B-SD1 was similar over the range of culture conditions tested and mechanisms of RP solubilisation are likely to be a combination of mechanisms that relate to both acidification and the production of organic anions. The effect of inoculation with P. radicum on plant growth and P nutrition was studied under glasshouse conditions using a sand culture assay that supplied defined sources of P. The plant growth and P response to P. radicum inoculation were determined in two separate experiments. In Experiment 1, plants were grown to pre-heading stage and supplied with either dibasic calcium phosphate (Ca-P), crystalline iron phosphate (Fe-P), rock phosphate (RP) or phytate (Pₒ) as the source of P. In Experiment 2, plants were harvested after 8 weeks and supplied with either NO₃⁻ or NH₄⁺ as the sole source of N and the P sources were either Ca-P or RP. In Experiment 1, the plant P response (defined as higher shoot P concentration and P uptake) to inoculation was dependent on the P source. The greatest plant P response to inoculation was observed for Ca-P and no significant P response was measured in plants that were supplied with Fe-P, RP or Pₒ. In pots that supplied Fe-P as the P source, there was an increase in shoot dry matter in response to P. radicum inoculation but this occurred without a concomitant plant P response. In Experiment 2, the plant P response to inoculation was dependent on the N source. In the presence of NH₄⁺, P. radicum significantly increased the availability of P sources RP and Ca-P. While there was no significant plant P response under NO₃⁻ supply, there was a significant increase in dry matter production due to P. radicum inoculation. When the data of Experiments 1 & 2 are taken together, results suggest that P. radicum possesses at least two mechanisms of plant growth promotion, (1) P solubilisation and (2) general growth promotion that is independent of P solubilisation. In agreement with P solubilisation in solution cultures, the P solubilisation mechanism of P. radicum in sand culture required NH₄⁺. The ability of P. radicum to increase plant growth independently of a plant P response gave further evidence of general growth promoting abilities of the fungus. While sand culture is a useful tool to elucidate the fungal mechanisms of plant growth promotion, this approach cannot fully reflect the complexity of the rhizosphere in non-sterile soil. Hence, a subsequent experiment was done to determine the effect of P. radicum on plant growth and P nutrition in a number of field soils. The P solubilising activity of P. radicum was determined in four Australian field soils using isotopic dilution. Three soils were chosen on the basis of their chemistry of P retention: (1) Minnipa soil from South Australia was chosen due to P retention associated with the highly alkaline calcareous nature of this soil; (2) Innisfail Queensland, in this soil P retention was dominated by reaction with Fe oxides; and (3) Mt Schank South Australia, a volcanic soil where P retention was predominantly associated with Al oxides. The fourth soil, from Mingenew Western Australia, was chosen due to previous reports that P. radicum inoculation increased the yield of field grown wheat (Bio-Care Technology, unpublished data). The four field soils were each labelled with KH₂ ³²PO₄ and the specific activity (³²P) of the wheat seedling tissue was measured after four weeks growth. When the data was averaged across all four soil types, inoculation with P. radicum caused a significant 11.7% increase in the shoot dry weight of these seedlings. However, P. radicum did not cause any consistent significant difference in the specific activity (³²P) of plants when compared to uninoculated control plants. These results suggested that P. radicum did not have a strong ability to solubilise P from the test soils, and mechanisms other than P solubilisation were in operation to stimulate plant growth. The production of plant growth regulators (PGR) was considered as a mechanism of plant growth promotion not related to P solubilisation. To further explore the hypothesis that the production of PGR acts as a mechanism of plant growth promotion, the ability of P. radicum to produce the auxin, indole-3-acetic acid (IAA) was investigated. Examination with thin-layer chromatography and the Avena coleoptile straight growth assay indicated that fractions of P. radicum culture medium with chemical characteristics similar to IAA (i.e. similar reaction to the Salkowski reagent and Rf as IAA) also possessed auxin-like activity. Using competitive enzyme linked immunosorbent assay (ELISA) it was found that in liquid culture amended with the precursor tryptophan, P. radicum produced IAA at concentrations up to 0.406 µM. These studies show that P. radicum can produce IAA under laboratory culture conditions. To determine the significance of IAA as a mechanism of plant growth promotion, further studies need to link effects on plant growth and development to the production of IAA by P. radicum. The ability of P. radicum to antagonise root pathogens and control root disease was considered as a further mechanism of growth promotion. Under in-vitro conditions, P. radicum produced hyphal growth patterns and enzymes (protease, β-1,3- and β-1,4-glucanase activity) that were indicative of hyperparasitism. Hyperparasitic growth was seen as hyphal coiling and branching of P. radicum against host hyphae of Rhizoctonia solani, Fusarium pseudograminearum and Pythium irregulare when these soilborne pathogens were studied in dual culture with P. radicum. The effect of P. radicum on the fungal root disease severity of take-all was studied using a seedling bioassay under glasshouse conditions. The ability of P. radicum to suppress take-all disease appeared to be related to the timing of P. radicum infection of wheat seedling roots and placement of the Ggt inoculum in relation to the roots. Compared to soils where Ggt inoculum was only distributed at distances >1 cm below the seed, uniform mixing of the Ggt inoculum throughout the soil negated the beneficial effect of P. radicum on plant growth and its ability to reduce take-all root lesion size. Conversely, early infection of wheat roots by P. radicum gave wheat seedlings some protection against take-all disease. Where treatment with P. radicum was effective, increasing the inoculum dose significantly reduced take-all lesion size. While P. radicum exhibited antagonism towards F. pseudograminearum, Py. irregulare, Bipolaris sorokiniana and R. solani cereal root pathogens in-vitro, further studies under non-sterile soil conditions are needed to evaluate the potential for P. radicum to reduce root disease caused by these fungi. In conclusion, it is unlikely that one single mechanism explains the beneficial effect of P. radicum on wheat growth. In-vitro studies showed that P. radicum has a number of attributes that could function as mechanisms of plant growth promotion. These attributes were, (1) P solubilisation, (2) production of IAA and (3) the ability to antagonise soilborne pathogens in-vitro and reduce the lesion size of the take-all disease in a seedling bioassay. Sand culture assays revealed that at least two plant growth mechanisms were in operation, (1) P solubilisation and (2) a general growth promotion mechanism that was independent of P solubilisation. In agreement with Whitelaw et al. (1999), the P solubilisation mechanism of P. radicum operates via an acidification mechanism. The effectiveness of this mechanism may be limited by the availability of NH₄⁺ in the rhizosphere. Since NH₄⁺ appears to be required for P solubilisation there may exist an interaction between P. radicum and ammoniacal fertilisers. This will have implications for its effectiveness in the field. In-vitro studies suggest that the general mechanism of growth promotion may be related to the production of PGRs such as IAA. In this aspect the known colonisation of the interior of wheat roots by P. radicum would ensure that IAA produced by the fungus is taken up by the root cell and less subject to chemical degradation and/or degradation by other soil microorganisms. Further studies are required to identify the effect of IAA production on plant growth and the effect of P. radicum inoculation on root disease severity in non-sterile soil. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1165226 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2004.

Graduation date: 1981

This study assesses the effect of politics on economic growth in developing societies. In this study I developed and applied an augmented production function model to 69 developing countries with several political variables: regime type, institutional freedom, political freedom, political stability, and ideological base. I investigated how changes of political contexts affect economic growth by applying non-linear least squares, and cross national time series techniques to the production function defensegrowth model utilizing time series data from 1960 to 2002. The results show that the impacts of political variables on economic growth are at least as significant as the economic variables; the externality of non-military spending has positive and significant impact on economic growth in the majority of countries; and the impacts of economic and military variables and their externalities’ effects on economic growth differ with different political contexts. The main findings of the study provide guidelines to policy decision makers in evaluating their “guns”-“butter” alternatives.

Adrenal function, blood metabolites, hematological parameters, growth, and carcass characteristics were compared in tropically-adapted (Brahman,) intermediate (Bonsmara and Bonsmara X Angus crossbred,) and temperate (Angus; n=10 each) beef steers. An adrenal gland challenge was conducted, entailing serial blood collection at 15-min intervals for a 12.5-h period, with administration of exogenous ACTH (0.1 IU/kg BW) 2.5-h into the experiment. Steers were maintained on Coastal bermudagrass pastures overseeded with ryegrass for five month; body weights and blood samples were obtained every 21 days. An anterior pituitary/adrenal gland challenge was conducted, entailing serial blood collection at 120, 90, 60 and 30 min prior to, and 10, 20, 30, 60 and 120 min following administration of exogenous CRH (0.1 ug/kg BW). Physical and physiological signs of heat stress were assessed, and blood samples were obtained for analysis. Exit velocity was measured. Carcass characteristics were determined post-slaughter. Statistical analysis was conducted using ANOVA for repeated measures, using least square means and Pearson’s and Spearman’s correlation analyses. Bonsmara and Bonsmara X Angus had lower basal cortisol (CS) than Angus and Brahman steers. Angus steers had greater adrenal responsiveness to ACTH, and responded faster to CRH than the other breedtypes. Bonsmara steers were slower in responding to CRH, and returning to basal CS following ACTH or CRH administration. Angus and Bonsmara X Angus grew faster during the finishing phase than Brahman or Bonsmara steers. Angus had higher quality grades than other breedtypes; rib-eye area and hot carcass weight were greater in Angus than Brahman steers, but similar among Angus, Bonsmara X Angus and Bonsmara steers. Angus and Brahman were less docile than Bonsmara and Bonsmara X Angus steers. Angus steers had higher respiration rates and serum concentrations of sodium, lower aldosterone during moderate heat exposure, and lesser serum concentrations of glucose, urea and cholesterol than tropically-influenced breedtypes. Angus had rectal and surface temperatures similar to those of Brahman, but greater than those of Bonsmara X Angus or Bonsmara steers. Intermediate breedtypes like the Bonsmara provide a compromise to producers, allowing them to address the demands of consumers while raising cattle better suited to survival in tropical climates.

This study examines the effect of ecophysiology on growth of cells and production of enzymes and secondary metabolites produced by the fungi Aspergillus niger (lysozyme) and a Phoma sp. (squalestatin S1). The effect of interactions of water activity (aw) (0.99-0.90), temperature (20, 30 and 35°C) and modifying aw solute (glycerol, NaCl) on growth and sporulation of a wild type strain of Aspergillus niger (W) and two genetically engineered lysozyme producing strains (L11, B1) was examined for the first time. Maximum growth rates were achieved for both strains (L11 and B1) under moderate aw levels. Optimum conditions for growth of strain L11 were estimated by means of contour plot surfaces and found to be 0.965 aw with glycerol as a solute at 35ºC (10.5 mm day-1). A model combining the effect of aw and temperature on growth of strains of Aspergillus niger, and comparison with data on food spoilage moulds in the literature was developed. The growth of two strains of A. niger, as a function of temperature (25-30oC) and aw (0.90-0.99) was developed. The estimation of the minimum aw (awmin) and optimal aw (awopt) levels were in accordance with data in the literature for a range of other Aspergillus and related species, regardless of the solutes used for aw modification. A central composition design was used to describe the effects of water activity (aw, 0.98, 0.97 and 0.96), inoculum size (2.7x105, 2.7x104 and 2.7x103 spores ml-1), and three autoclaving procedure (A = all components autoclaved together, B = medium autoclaved + maltose filtered and, C = medium autoclaved + maltose & soya milk filtered) on the production of lysozyme by two genetically-engineered strains of Aspergillus niger (B1 and L11) in a liquid culture fermentation. Although both strains produced similar lysozyme concentrations (15 mg l-1), different production patterns were found under the experimental conditions. However, strain B1 produced relatively higher amounts of lysozyme under water stress (0.96 aw) with all the substrates autoclaved together. Subsequently, a central composition design was used to investigate: different immobilized polymer types (alginate and pectate), polymer concentration (2 and 4% (w/v)), inoculum support ratios (1:2 and 1:4) and gel-inducing agent concentration (CaCl2, 2 and 3.5% (w/v)) on lysozyme production. Overall immobilization in Ca-pectate resulted in higher lysozyme production compared to immobilization in Ca-alginate. Similar effects were observed when the polymer concentration was reduced. A 13 fold higher lysozyme production was achieved with Ca-pectate in comparison to Ca-alginate (20-23 and 0.5-1.7 mg l-1 respectively). Polymer modifications also significantly affected the final pH and aw of the immobilized cell fermentation. The aw factor is a very significant parameter in the immobilization design. A combined statistical methodology of orthogonal design L27(313) and surface response methodology was applied to optimize the composition and concentration of a liquid fermentation medium for the production of squalestatin S1 by a Phoma species. Confirmatory experiments of the optimal medium composition produced average concentrations of 434 mg l 1 in five days fermentation at 25oC. This represented an improvement over 60% of the maximum concentration achieved in the initial experiment and a two-fold higher productivity in comparison with reported productivities of S1 in liquid fermentations with different fungal species. Different liquid height and column diameter (HL/Hr) ratios 3.7, 7.4 and 11.4 were studied in a bubble column (Dr=0.07 m) with a porous plate gas distributor, to find the effect on the gas hold up, power consumption (PG/VL) and volumetric mass transfer coefficient, kLa performance, under different superficial gas velocities calculated from the liquid properties and flow rates (2, 4, 6 and 8 l min-1) and temperatures (15, 25 and 30oC). Two kLa models were proposed based on the geometrical ratio (HL/Dr) and superficial gas velocity (m s-1) (R2=0.951), and power consumption (PG/VL) (R2=0.950). A free cell fermentation was performed in the bubble column, ratio (HL/Dr)= 3.7 and superficial gas velocity U= 0.120 m s-1, at 25oC. The S1 production reached a level of 420 mg l 1. The bioreactor scale up succeeded in maintaining the high S1 concentration obtained in our previous work 434 mg l 1 in Erlenmeyer flasks but in a shorter time. A Plackett-Burman design was used to improve the S1 produced by different immobilized designs. The immobilized cell fermentation design considered: polymerization with alginate and polygalacturonate and copolymerization, polymer concentration (alginate 3, 3.5 and 5 % w/v and pectate 4, 6 and 8 % w/v), 0.98, 0.96 and 0.94 aw levels, inoculum levels of 10, 20 and 30 % wt. v/v, gel-inducer (CaCl2) 3, 4 and 5 % w/v, gel-reinforce agent 0, 0.75 and 1.5 g l-1, air flow 4, 6 and 8 l min-1. Production of S1 reached levels of 883 mg l-1 which represent a 34 % improvement over the 660 mg l 1 produced in a stirred tank bioreactor (STR) with a free cell fermentation.