Alkaline Protease Production from Brevibacterium luteolum (MTCC 5982) Under Solid-State Fermentation and Its Application for Sulfide-Free Unhairing of Cowhides.

Enzyme-based unhairing in replacement of conventional lime sulfide system has been attempted as an alternative for tackling pollution. The exorbitant cost of enzyme and the need for stringent process control need to be addressed yet. This study developed a mechanism for regulated release of protease from cheaper agro-wastes, which overcomes the necessity for stringent process control along with total cost reduction. The maximum protease activity of 1193.77 U/g was obtained after 96 h of incubation with 15% inoculum of the actinomycete strain Brevibacterium luteolum (MTCC 5982) under solid-state fermentation (SSF). The medium after SSF was used for unhairing without the downstream processing to avoid the cost involved in enzyme extraction. This also helped in the regulated release of enzyme from bran to the process liquor for controlled unhairing and avoided the problem of grain-pitting. Unhairing process parameters were standardized as 20% enzyme offer, 40% Hide-Float ratio at 5 ± 1 rpm, and process pH of 9.0. The cost of production of 1000 kU of the protease was calculated as 0.44 USD. The techno-economic feasibility studies for setting up an SSF enzyme production plant showed a high return on investment of 15.58% with a payback period of 6.4 years.

Utilization of fish meal and fish oil for production of Cryptococcus sp. MTCC 5455 lipase and hydrolysis of polyurethane thereof.

Fish meal has been used as an additional nitrogen source and fish oil as inducer for the growth and production of lipase from Cryptococcus sp. MTCC 5455. A response surface design illustrated that the optimum factors influencing lipase production were fish meal, 1.5 %, w/v, Na2HPO4, 0.2 %, w/v, yeast extract, 0.25 %, w/v and sardine oil, 2.0 %, w/v with an activity of 71.23 U/mL at 96 h and 25 °C, which was 48.39 % higher than the conventional one-factor-at-a-time method. The crude concentrated enzyme hydrolyzed polyurethane (PUR) efficiently and hydrolysis was 94 % at 30 °C and 96 h. The products, diethylene glycol and adipic acid were quantified by HPLC and scanning electron microscopic studies of the degraded polymer showed significant increase in size of the holes from 24 to 72 h of incubation. Hydrolysis of PUR within 96 h makes the lipase novel for disposal of PUR and provides an innovative solution to the problems created by plastic wastes.

Enzymatic treatment to improve the quality of black tea extracts.

Enzymatic extraction was investigated to improve the quality of black tea extracts with pretreatment of pectinase and tannase independently, successively and simultaneously. Pectinase improved the extractable-solids-yield (ESY) up to 11.5%, without much of an improvement in polyphenols recovery, while tannase pre-treatment showed a significant improvement in polyphenols recovery (14.3%) along with an 11.1% improvement in ESY. Among the four treatments, tannase-alone treatment showed the maximum improvement in tea quality, with higher polyphenols-in-extracted solids. Treatments involving tannase resulted in the significant release of gallic acid, due to its hydrolytic activity, leading to greater solubility besides favourably improving TF/TR ratio. The results suggested that employing a single enzyme, tannase, for the pre-treatment of black tea is desirable. Enzymatic extraction may be preferred over enzymatic clarification as it not only displayed reduction in tea cream and turbidity but also improved the recovery of polyphenols and ESY in the extract, as well as maintaining a good balance of tea quality.

Scale up of a novel tri-substrate fermentation for enhanced production of Aspergillus niger lipase for tallow hydrolysis.

A novel tri-substrate fermentation (TSF) process was developed for the production of lipase from Aspergillus niger MTCC 2594 using agro-industrial residues, wheat bran (WB), coconut oil cake (COC) and an agro-product, wheat rawa (WR). The lipase activity was 628.7+/-13 U/g dry substrate (U/gds) at 30 degrees C and 96 h and growth studies indicated that addition of WR significantly augmented the biomass and lipase production. Scale up of lipase production at 100g and 3 kg (3 x 1 kg) tray-level batch fermentation resulted in 96% and 83.0% of enzyme activities, respectively, at 72 h. Maximum activity of 745.7+/-11U/gds was obtained, when fermented substrate was extracted in buffer containing 1% (w/v) sodium chloride and 0.5% (w/v) Triton X-100. Furthermore, the direct application of fermented substrate for tallow hydrolysis makes the process economical for industrial production of biofuel.

Corn steep liquor as a nutrition adjunct for the production of Aspergillus niger lipase and hydrolysis of oils thereof.

Corn steep liquor (CSL) has been used as a nutrition adjunct for the production of an extracellular lipase from Aspergillus niger, which has immense importance as an additive in laundry detergent formulations. A five-level four-factorial central composite design was chosen to determine the optimal medium components with four critical variables, namely, CSL, NH4H2PO4, Na2HPO4, and sesame oil, that were found to be influential for lipase production by the classical one-factor-at-a-time method. The model suggested that all of the factors chosen had a significant impact on lipase production, and the optimum values of the influential parameters were CSL, 2.0%, w/v; NH4H2PO4, 0.05%, w/v; Na2HPO4, 0.75%, w/v; and sesame oil, 2.0%, w/v, with an activity of 26.7 U/mL at 48 h and 30 degrees C, which was 2.16-fold higher than the initial activity (12 U/mL) obtained by the conventional one-factor-at-a-time method. Furthermore, the enzyme has good potential for the hydrolysis of vegetable oils and fish oils, and a hydrolytic ratio of 88.73% was obtained with palm oil at 48 h. The utilization of CSL and sesame oil for lipase production from A. niger makes the process green, because both are renewable substrates and economically viable at an industrial scale.

Interaction of transport resistances with biochemical reaction in packed-bed solid-state fermentors: effect of temperature gradients.

In solid-state fermentation, the interaction of transport phenomena with biochemical reactions has a considerable effect on the productivity of the bioreactor. Previous work on solid-state fermentation in tray fermentors in our laboratory indicated that heat transfer resistance results in steep temperature gradients within the solid substrate bed, which in turn adversely affect the biochemical reaction and enzyme activity. This problem of heat accumulation during the course of fermentation has been alleviated to a considerable extent using a packed-column bioreactor with forced aeration in the present work. Experimental studies were conducted in a packed-column bioreactor utilizing wheat bran as substrate and the fungus Aspergillus niger CFTRI 1105 for the production of the enzyme amyloglucosidase. The enzyme activities were estimated and temperatures were recorded at different bed heights, for different air flow rates during the course of fermentation. The results indicated that the temperature gradients caused by heat transfer resistances were reduced considerably with corresponding increases in enzyme activity.

Interaction of transport resistances with biochemical reaction in packed bed solid state fermenters: the effect of gaseous concentration gradients.

Mass transfer plays an important role in solid state fermentation (SSF) systems. Earlier work on SSF in tray bioreactors indicated that steep gaseous concentration gradients developed within the substrate bed, owing to mass transfer resistances, which may adversely affect the bioreactor performance. For all practical purposes these gradients have been eliminated using a packed bed column bioreactor with forced aeration. Gaseous concentrations (oxygen and carbon dioxide) and enzyme activities were measured at various bed heights for various air flow rates during the course of fermentation. The results indicated that concentration gradients were decreased effectively by increasing air flow rate. For example, the actual oxygen and carbon dioxide concentration gradients reduced from 0.07% (v/v) cm-1 and 0.023% (v/v) cm-1 to 0.007% (v/v) cm-1 and 0.0032% (v/v) cm-1 respectively when the air flow rate was increased from 5 dm3 min-1 to 25 dm3 min-1. This resulted in an overall improvement in the performance of the bioreactor in terms of enzyme production.

Gas concentration and temperature gradients in a packed bed solid-state fermentor.

In solid-state fermentation (SSF), interaction of heat and mass transfer with biochemical reaction (growth associated enzyme production) affects the bioreactor performance. This interaction was earlier observed to cause temperature and gaseous concentration gradients which reduced the effective bed height of the bioreactor. Since forced aeration is known to alleviate this problem, a packed column bioreactor with forced aeration was employed in the present study. Using wheat bran and Aspergillus niger CFTRI 1105, experiments were conducted for the production of the enzyme amyloglucosidase at various air flow rates. Temperatures and gas concentrations were recorded and enzyme activities estimated at different bed heights during the course of SSF. Gas concentration and temperature gradients decreased with increasing air flow rate. The packed column allowed the use of larger bed heights and yielded higher enzyme activities (6,260 Units/gDMB) than trays (345 Units/gDMB). Enzyme activity was affected more by temperature than concentration gradients, and increased with air flow rates.