Performance of a Two-Stage Membrane System for Bromelain Separation from Pineapple Waste Mixture as Impacted by Enzymatic Pretreatment and Diafiltration

Latest Advances in Protein-Recovery Technologies from Agricultural Waste

In recent years, downstream bioprocessing industries are venturing into less tedious, simple, and high-efficiency separation by implementing advanced purification and extraction methods. This review discusses the separation of proteins, with the main focus on amylase as an enzyme from agricultural waste using conventional and advanced techniques of extraction and purification via a liquid biphasic system (LBS). In comparison to other methods, such as membrane extraction, precipitation, ultrasonication, and chromatography, the LBS stands out as an efficient, cost-effective, and adaptable developing method for protein recovery. The two-phase separation method can be water-soluble polymers, or polymer and salt, or alcohol and salt, which is a simpler and lower-cost method that can be used at a larger purification scale. The comparison of different approaches in LBS for amylase purification from agricultural waste is also included. Current technology has evolved from a simple LBS into microwave-assisted LBS, liquid biphasic flotation (LBF), thermoseparation (TMP), three-phase partitioning (TPP), ultrasound-assisted LBS, and electrically assisted LBS. pH, time, temperature, and concentration are some of the significant research parameters considered in the review of advanced techniques.

Performance of Single and Two-Stage Cross-Flow Ultrafiltration Membrane in Fractionation of Peptide from Microalgae Protein Hydrolysate (Nannochloropsis gaditana)

Cross-flow ultrafiltration (UF) membrane with two different configurations; single (10 kDa and 5 kDa) and two-stage (10/5 kDa) in fractionating microalgae protein hydrolysate (MPH) were studied to obtain a low molecular weight of peptide. The effect of flow rate, trans-membrane pressure (TMP), and pH in fractionating MPH were evaluated based on permeate flux and peptide transmission. The results showed that, for single UF membrane, optimum operating parameters were at a flow rate of 23 mL/min, TMP of 1.5 bar, and pH of 9, with permeate flux of 43.65 L/m2 h (10 kDa) and 55.42 L/m2 h (5 kDa) and peptide transmission of 58.20% (10 kDa) and 67.34% (5 kDa). Meanwhile, for two-stage (10/5 kDa) UF membrane, the best parameters were observed at a flow rate of 23 mL/min, TMP of 1.5 bar, and pH of 2, with permeate flux of 69.85 L/m2 h and peptide transmission of 79.13%. Fractionation of MPH with two-stage UF membrane was observed to be better at producing a low molecular weight of peptide compared to single UF membrane. In conclusion, it was possible to produce permeate flux with a high amount of low molecular weight of peptide by controlling the operating parameters with the suitable configuration membrane.

Fractionation and activity profiling of fruit bromelain from pineapples of Phuket variety growing in Thailand

Bromelain is a type of protease found in both fruits and stems of pineapples. Stem bromelain has been extensively studied and is commercially available for applications in various industries. In contrast, studies of fruit bromelain are quite limited since most of pineapples have been consumed freshly, canned or juiced. Nowadays, the consumption of canned fruits, including canned pineapples has decreased greatly. Fruit bromelain could be a new growth point for pineapple industry. In this study, fruit bromelain was extracted from the pineapple juice of Phuket variety and some of its properties were studied. The enzyme was purified by precipitation using ammonium sulfate fractionation followed by ion-exchange and gel filtration chromatography. Consequently, the protease purification level was increased by 95.2 fold. The final specific activity was getting to 448,590 U/mg on average, dominated by cysteine proteases, with optimal activity at 45°C and pH ranging from 6 to 8. The study facilitates the molecular and application research of fruit bromelain. PRACTICAL APPLICATIONS: The research has been carried out at Funong Food Technology Co., Ltd., Guangdong, China, which produces primarily pineapple chunks and juice. As plenty of by-products, like peels and cores of pineapples, are produced, the techniques are employed to extract bromelain from the by-products. The techniques reported in this work are not new or advanced, however, they are applicable during the manufacturing process and the related equipment is easy to set up and operate. What's more, the practical application of the techniques is cost-effective for the manufactories. Take Funong Food Technology Co., Ltd. as an example, they was using 80% saturation ammonium sulfate to precipitate protein from pineapple juice and obtained a bromelain with activity of approximately 8,000 U/mg and yield of 1.7 kg per ton of juice. With the application of the techniques reported in this work, bromelain was first extracted by ammonium sulfate gradient precipitation, and then purified through ion-exchange and gel filtration chromatography. Each step of precipitation and purification generates a different level of activity and recovery of bromelain, ranging from around 2,506 to 448,590 U/mg, which allows for the production of bromelain according to the requirement of the market and brings more profits.