Model predictive control of pH in tubular photobioreactors

This paper presents the development and implementation of a branch-and-bound on–off model-based predictive control (MPC) strategy aimed at controlling pH and minimising CO₂ losses in a microalgal tubular photobioreactor. These kinds of photobioreactors are usually controlled by means of an on–off valve and thus classical on–off switching controllers are implemented, without taking into account plant dynamics. In the considered operating range, the nonlinearity of the system is not severe and thus a linear model of the pH evolution in spite of changes in CO₂ injection and in solar radiation has been obtained and used within a MPC framework to achieve desired regulation properties trying to minimise CO₂ losses, as one of the major costs in this installation is the supply of carbon dioxide and its transfer to the culture, amounting to about one-third the cost of the largest scale systems. The paper also shows the results obtained when applying the technique to the real photobioreactor.     

Micromechanical compartments for biotechnological applications: fabrication and investigation of liquid evaporation

Arrays of microcompartments for combinatorial chemistry and biotechnological applications have been fabricated by means of photolithography and anisotropic chemical wet etching. Integration levels of 25 000 per 4″ wafer have been achieved. Optically transparent membranes or microsieves allowing for rinsing between process steps can be incorporated. The liquid evaporation from the microcompartments has been investigated using compartments of different shape. The evaporation rate can be reduced by a factor of by using properly designed microcompartments with small openings. For the investigation of thermally biochemical reactions a microcompartment array with integrated thermo control has been developed, which allows the adjustment of thermal gradients over a 4″ wafer. Peak temperatures exceeding 90°C at the centre of the wafer as well as temperature gradients with ΔT=30°C can be demonstrated.     

工科院校生物技术专业人才培养模式的探讨

根据吉林化工学院特色及生物技术专业的特点进行了化工特色生物技术新专业人才培养模式的探讨,构建了符合工科化工院校实际的,具有化工特色的生物技术新专业人才培养方案、课程体系、教学方法改革体系,为工科化工院校生物技术专业建设和人才培养提供参考。     

生物技术在化学工业中的应用

指出了生物技术研究和开发的实用化、商业化的趋势已为传统的化学工业注入新的活力；综述了生物技术在化学工业中的应用，表明生物合成是一种合成化学品的高效新方法，生物技术提供了有机化学品的新来源与生活必需品的新资源；生物技术提供了新的无害化工工艺。     

膜在生物技术中的应用

综述了膜在生物技术方面的应用。概述了纳滤膜的基本原理。着重介绍了纳滤膜在食品工业，生物化工与制药工业，染料工业等方面的一些应用。     

State estimation and predictive control of fed-batch cultures of hybridoma cells

Fed-batch cultures of hybridoma cells are commonly used for the production of monoclonal antibodies (MAb). In this study, a simple macroscopic model of the cell culture is used, which is based on the overflow metabolism paradigm. This allows to specify optimal culture conditions, and the natural formulation of a nonlinear model predictive control strategy (NMPC). As not all the component concentrations are available for measurement, system observability is analyzed, and an unscented Kalman filter (UKF) is designed, which provides satisfactory estimates of glucose and glutamine concentrations. Robustness of the NMPC scheme is investigated, as well as the combined UKF+NMPC scheme, through a minimax robust version and the closed-loop system.     

Some quantitative data on bacterial attachment to pyrite

Bacterial attachment and biofilm formation are important for microbial bioleaching of metal sulfides, however, many details of the role played by bacteria are still unknown. Attachment as the first step in biofilm formation is critical. Our investigations are focused on these processes to control bacterial bioleaching processes.In moderately thermophilic pure cultures of Acidithiobacilluscaldus and Leptospirillumferriphilum, only the latter one showed significant attachment and biofilm formation to metal sulfides. In pure cultures of the mesophilic strains Acidithiobacillusspp., Leptospirillumferrooxidans, Ferrimicrobiumacidiphilum and a novel undescribed leaching organism designated SPIII/3, attachment was significant by L. ferrooxidans, At. thiooxidans and SPIII/3.In general, interaction of different species in mixed cultures resulted in increased attachment, increased production of extracellular polymeric substances (EPS) and leaching. Bacteria like Leptospirillumspp. enhanced the attachment of other species in mixed biofilms. Another finding is that large areas of the surface of minerals remain uncolonized, whereas at some places bacteria attach in clusters.Based on these findings we conclude that attachment and thereby bacterial leaching can be improved by the production of EPS by several strains especially in combination with Leptospirillumspp.     

Extracellular polymeric substances (EPS) from bioleaching systems and its application in bioflotation

The use of EPS-producing heterotrophic and chemolithotrophic bacteria in bioflotation processes have been investigated for the last two decades. These studies have mostly been confined to laboratory microflotation tests using pure cultures. In this study the use of EPS, extracted from bioleaching consortia, to float chalcopyrite was evaluated and key process parameters such as pH, flotation time and the concentration of collector, bacterial cells and EPS were optimised. Analyses of the EPS extracted from various bioleach systems indicated that the EPS consisted mainly of carbohydrates, proteins and uronic acids. Microflotation tests using free EPS yielded a chalcopyrite recovery of 77% when chalcopyrite was floated alone and 70% during the separation of a mixture of pure chalcopyrite and pure pyrite compared to 32% when using SIBX only. The results obtained suggested that the flotation of chalcopyrite could be significantly increased in the presence of EPS extracted from bioleaching populations.     

Fermentative Production of L‐Lysine‐L‐lactate with Fractionated Press Juices from the Green Biorefinery

Lactic acid (LA) is a platform chemical for a future bio‐based economy. Aminium lactates act as intermediates for the production of lactic acid sequence products like lactide. It could be demonstrated that, after separation of proteins from alfalfa press juice, the supernatant can be used as fermentation media for the production of the aminium lactate, L‐lysine‐L‐lactate.     

Effect of pH on Aerobic Granulation and Treatment Performance in Sequencing Batch Reactors

Two sequencing batch reactors were operated to investigate the effect of influent alkalinity and reactor pH on aerobic granulation. In the first reactor R1 with high influent alkalinity the pH was adjusted in the neutral range, and in the second reactor R2 with low alkalinity the pH was held within the acidic range. The R1‐dominating species were bacteria and the appearance time of granules was three weeks after reactor start‐up. On the other hand, the acidic environment of R2 provided favorable conditions for fungal growth, and rapid granule formation occurred within the first week of operation. The varying microbial structure of granules resulted in different reactor performance in terms of evolution time and morphology of granules, suspended solids in the reactors, settling ability of granules, effluent quality of treated wastewater, and physical strength of the granules.